FM 6310, 6320 Combustible Gas Detectors

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Approval Standard

for

Combustible Gas Detectors

Class Number 6310, 6320

January 2001

Based in part on ANSI/ISA-12.13.01-2000, Performance Requirements for Combustible Gas Detectors.

2002 FM Approvals LLC. Portions ISA. All rights reserved.


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Foreword

FM Approvals are intended to verify that the products and services described will meet stated conditions ofperformance, safety and quality useful to the ends of property conservation. The purpose of FM ApprovalStandards is to present the criteria for FM Approval of various types of products and services, as guidance forFM Approvals personnel, manufacturers, users and authorities having jurisdiction.

Products submitted for Approval shall demonstrate that they meet the intent of the Approval Standard, and thatquality control in manufacturing and/or applications shall ensure a consistently uniform and reliable product orservice. FM Approval Standards strive to be performance-oriented and to facilitate technological development.

For examining equipment, materials and services, FM Approval Standards:

a) must be useful to the ends of property conservation by preventing, limiting or not causing damageunder the conditions stated by the Approval listing; and

b) must be readily identifiable.

Continuance of Approval and Listing depends on compliance with the Approval agreement, satisfactoryperformance in the field, on successful re-examinations of equipment, materials, and services as appropriate, andon periodic follow-up audits of the manufacturing facility or service/application.

FM Approvals LLC reserves the right in its sole judgement to change or revise its standards, criteria,methods, or procedures.


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TABLE OF CONTENTS

1. INTRODUCTION ..................................................................................................................................................................... 1

1.1 Purpose .............................................................................................................................................................................. 1

1.2 Scope ................................................................................................................................................................................. 1

1.3 Basis for Requirements ..................................................................................................................................................... 2

1.4 Basis for FM Approval ..................................................................................................................................................... 2

1.5 Basis for Continued Approval .......................................................................................................................................... 3

1.6 Effective Date .................................................................................................................................................................... 3

1.7 System of Units .................................................................................................................................................................. 3

1.8 Applicable Standards ......................................................................................................................................................... 3

1.9 Definitions ......................................................................................................................................................................... 3

2. GENERAL REQUIREMENTS ............................................................................................................................................... 6

2.1 Review of Documentation ................................................................................................................................................ 6

2.2 Markings ............................................................................................................................................................................ 6

2.3 Manufacturers Installation and Operation Manuals ........................................................................................................ 7

2.4 Construction and Functions ............................................................................................................................................ 102.5 Test Equipment Calibration ............................................................................................................................................ 12

3. PERFORMANCE REQUIREMENTS ................................................................................................................................. 12

3.1 General ............................................................................................................................................................................. 12

3.2 Samples and Sequence .................................................................................................................................................... 13

3.3 Preparation of instrument ................................................................................................................................................ 13

3.4 Conditions for test and test area ..................................................................................................................................... 13

3.5 Selectable gas/range instruments .................................................................................................................................... 15

3.6 Un-powered preconditioning storage .............................................................................................................................. 15

3.7 Drop test .......................................................................................................................................................................... 16

3.8 Vibration .......................................................................................................................................................................... 16

3.9 Calibration ....................................................................................................................................................................... 16

3.10 Accuracy ........................................................................................................................................................................ 17

3.11 Temperature ................................................................................................................................................................... 17

3.12 Step change response .................................................................................................................................................... 18

3.13 Humidity variation ........................................................................................................................................................ 18

3.14 Air velocity variation .................................................................................................................................................... 19

3.15 Supply voltage variation ............................................................................................................................................... 19

3.16 Electromagnetic Interference (EMI) ............................................................................................................................. 20

3.17 Long-term stability ........................................................................................................................................................ 20

3.18 Flooding with undiluted gas ......................................................................................................................................... 22

3.19 Additional Tests ............................................................................................................................................................. 22

4. OPERATIONS REQUIREMENTS ....................................................................................................................................... 23

4.1 Demonstrated Quality Control Program ......................................................................................................................... 23

4.2 Facilities and Procedures Audit (F&PA) ........................................................................................................................ 23

APPENDIX A: GENERAL INFORMATION .......................................................................................................................... 24

A-1 Approval Application Requirements ............................................................................................................................. 24A-2 Requirements for Samples for Examination ................................................................................................................. 25

APPENDIX B: UNITS OF MEASUREMENT ......................................................................................................................... 26


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1. INTRODUCTION

1.1 Purpose

1.1.1 This standard provides minimum requirements for combustible gas detection instruments forFM Approval.

1.1.2 FM Approval criteria may include, but are not limited to, performance requirements, marking require-ments, examination of manufacturing facility(ies), audit of quality assurance procedures, and a follow-upprogram.

1.2 Scope

1.2.1 This standard is concerned with the details of construction, performance and testing of portable, mobileand stationary electrical instruments that sense the presence of combustible gas or vapor concentrations inair. Based on associated requirements specified in Section 3, this standard considers the suitability of theinstruments or parts thereof for use in Class I, hazardous (classified) locations as defined by the NationalElectrical Code (ANSI/NFPA 70).

NOTE: IT IS STRESSED THAT ALTHOUGH COMBUSTIBLE GAS DETECTORS WARN OF ANEXPLOSION, THEY DO NOT NECESSARILY WARN OF TOXIC GAS RELEASES. IT IS ALSOSTRESSED THAT FINAL AND LONG-TERM EFFECTIVENESS OF ANY COMBUSTIBLE GASDETECTION EQUIPMENT DEPENDS HEAVILY UPON THE USER, WHO MUST BERESPONSIBLE FOR ITS PROPER APPLICATION, INSTALLATION, USE, AND REGULARMAINTENANCE.

1.2.2 This standard applies to line-voltage operated instruments rated at 250V nominal or less, and to portable,mobile, or stationary-type instruments supplied by battery of a non-rechargeable (primary) type or arechargeable (secondary) type.

1.2.3 For intrinsically safe instruments, this standard applies only to systems which utilize defined associatedintrinsically safe apparatus (protective barrier assemblies). Entity concept does not apply to theperformance Approval of combustible gas detectors.

1.2.4 This standard addresses combustible gas detection instruments intended to provide an indication or alarm,the purpose of which is to give warning of potential hazard.

1.2.5 This standard does not address gas detection instruments of the laboratory or scientific type used foranalysis or measurement, instruments used for process control and process monitoring purposes, open path(line of sight) area monitors, or instruments used for residential purposes.

1.2.6 This standard is written for gas detection instruments that are intended to detect gas concentrations in airin the range from zero up to the lower flammable limit (LFL), since this is the most commonly used range

for instruments intended to measure or monitor the degree of explosion hazard. This does not precludeinstruments intended for higher concentration ranges, such as those intended to warn of a drop inconcentration from a high value down to the upper flammable limit (UFL).

1.2.7 For instruments used for sensing the presence of oxygen, non-flammable toxic gases, and flammable gasesor vapor concentrations in air, this standard applies only to the portion of the instrument sensing theflammable gases or vapor concentrations in air.

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1.2.8 FM Approval is limited to instrument applications where: (a) calibration is performed using either the gasto be monitored or another gas for which response conversion data appears in the instruction manual; and(b) the instrument alarm set point is within 10% LFL of the calibration concentration of the gas to bemonitored, e.g. for an alarm set point value of 50% LFL, the calibration concentration must be between40% LFL and 60% LFL.

NOTE 1: INSTRUMENT PERFORMANCE TESTING ON COMBUSTIBLE GAS DETECTORSDURING A FM APPROVAL EXAMINATION IS CONDUCTED USING A SINGLE GAS, ASSPECIFIED IN SECTION 3.9.

NOTE 2: IT IS THE RESPONSIBILITY OF THE INSTRUMENT MANUFACTURER TODEMONSTRATE THE VALIDITY OF RESPONSE CONVERSION DATA DURING THE APPROVALEXAMINATION PER SECTION 1.3.3.

1.3 Basis for Requirements

1.3.1 The requirements of this Standard are based on experience, research and testing, and/or the standards ofother national and international organizations. The advice of manufacturers, users, trade associations,

jurisdictions and/or loss control specialists has also been considered.

1.3.2 The construction, testing and marking required by this standard correspond, in general, to ISA S12.13.01,Part I 2000, Performance Requirements, Combustible Gas Detectors.

1.3.3 The requirements of this standard reflect tests and practices used to examine characteristics of combustiblegas detectors for the purpose of obtaining FM Approval. These requirements are intended primarily asguides, and strict conformity is not always mandatory. Combustible gas detectors having characteristicsnot anticipated by this standard may be Approved if performance equal or superior to that required by thisstandard is demonstrated, or if the intent of the standard is met. Alternatively, gas detectors which do meetall the requirements identified in this standard may not be Approved if other conditions which adverselyaffect performance exist or if the intent of this standard is not met.

1.4 Basis for FM Approval

FM Approval is based upon satisfactory evaluation of the product and the manufacturer in the following majorareas:

1.4.1 Examination and tests on production samples shall be performed to evaluate

the suitability of the product

the proper operation and performance of the product as specified by the manufacturer and required byFM Approvals; and as far as practical,

the durability and reliability of the product.

1.4.2 An examination of the manufacturing facilities and audit of quality control procedures shall be made to

evaluate the manufacturers ability to produce a product identical to that which was examined and tested,and the marking procedures used to identify the product. These examinations are repeated as part ofFM Approvals product follow-up program.

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1.5 Basis for Continued Approval

Continued Approval is based upon:

production or availability of the product as currently Approved;

the continued use of acceptable quality assurance procedures;

satisfactory field experience;

compliance with the terms stipulated in the Approval Agreement; and

examination of production samples for continued conformity to requirements.

Also, as a condition of retaining Approval, manufacturers may not change a product or service without priorauthorization by FM Approvals.

1.6 Effective Date

The effective date of an Approval standard mandates that all products tested for Approval after the effective dateshall satisfy the requirements of that standard. Products Approved under a previous edition shall comply with thenew version by the effective date or forfeit Approval.

The effective date of this Standard is January 1, 2005 for compliance with all requirements.

1.7 System of Units

Units of measurement in this standard are International System (SI) units. Appendix B lists conversion formulasfor equivalents in United States (U.S.) Customary units.

1.8 Applicable Standards

1.8.1 This standard is intended to be used in conjunction with FM Approval Standard 3600 which includes thegeneral requirements that apply to all types of protection for hazardous (classified) locations.

1.8.2 Any portion of a gas detection instrument that is intended for installation or use in a location where gasor vapor concentration is to be detected shall be suitable for use in Class I, Division 1 or 2 or Class I, Zone0, 1 or 2 hazardous locations in accordance with the group classification of the gas. See FM ApprovalStandard 3600.

NOTE 1: IN ACCORDANCE WITH THE NATIONAL ELECTRICAL CODE (ANSI/NFPA 70),ONLY INSTRUMENTS WHICH UTILIZE INTRINSIC SAFETY (ia) CAN BE APPROVED FOR USEIN CLASS I, ZONE 0. INSTRUMENTS WHICH UTILIZE FLAMEPROOF (d) EITHER ENTIRELY ORIN CONJUNCTION WITH INTRINSIC SAFETY, CANNOT BE APPROVED FOR USE IN CLASS I,ZONE 0.

1.9 Definitions

For purposes of this standard, the following terms apply:

1.9.1 Alarm: An audible, visual or physical presentation designed to alert the instrument user that a specificlevel of combustible gas concentration has been reached or exceeded.

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1.9.2 Alarm only instrument: An instrument providing an alarm(s), but which does not have an integral meteror other readout device indicating current combustible gas concentration levels.

1.9.3 Alarm set-point: The selected gas concentration level(s) at which an indication, alarm, or other outputfunction is initiated.

1.9.4 Calibration: The act of adjusting an instrument to zero and setting the desired span. This procedureis repeated frequently by the instrument user and included in certain tests called for in this standard. Itverifies that the response of an instrument to a known gas concentration is within performance require-ments of this standard. This may necessitate adjustment of zero, span, and alarm set point.

1.9.5 Calibration gas concentration: The concentration of the combustible gas in ambient air used to set theinstrument span or alarm set point.

1.9.6 Clean air: Air that is free of combustible gases, vapors or contaminating substances.

1.9.7 Class 6310: FM Approvals designation for all portable gas detectors.

1.9.8 Class 6320: FM Approvals designation for all stationary gas detectors.

1.9.9 Combustible gas: Any flammable gas or vapor that, in sufficient concentration by volume in air, canbecome the fuel for an explosion or fire hazard. Materials that cannot produce sufficient gas or vapor toform a flammable mixture at ambient or operating temperatures and mists formed by the mechanicalatomization of combustible liquids are NOT considered to be combustible gases.

NOTE: FOR CONVENIENCE, THE SHORTER TERM GAS MAY BE USED AS ANABBREVIATION FOR COMBUSTIBLE GAS OR VAPOR WITHIN THIS DOCUMENT.

1.9.10 Control unit: That portion of a gas detection instrument that is not directly responsive to the combus-tible gas, but which responds to the electrical signal obtained from one or more detector heads. This unitproduces the output function when such gas is present at the detector head location.

1.9.11 Detector head: The gas responsive portion of a gas detection instrument located in the area wheresensing the presence of gas is desired. It may be integral with or removed from its control unit.

NOTE: THE DETECTOR HEAD MAY INCORPORATE, IN THE SAME HOUSING, CIRCUITRYSUCH AS SIGNAL PROCESSING AND AMPLIFYING COMPONENTS IN ADDITION TO THEGAS SENSING ELEMENT (SENSOR).

1.9.12 Diffusion: A method by which an atmosphere being monitored gains access to the gas sensing elementby nature of molecular movement or natural convection.

1.9.13 Flammable range: The range of flammable vapor concentrations or gas-air mixtures in which propa-gation of flame will occur on contact with a source of ignition.

NOTE 1: THE TERMS LOWER FLAMMABLE LIMIT (LFL) AND LOWER EXPLOSIVELIMIT (LEL) ARE DEEMED TO BE SYNONYMOUS. THE TERMS UPPER FLAMMABLE

LIMIT (UFL) AND UPPER EXPLOSIVE LIMIT (UEL) ARE DEEMED TO BE SYNONYMOUS.FOR EASE OF REFERENCE, THE TWO ABBREVIATIONS LFL AND UFL ARE USED HERE-INAFTER TO DENOTE THESE TWO SETS OF TERMS. IT SHOULD BE RECOGNIZED THATPARTICULAR AUTHORITIES HAVING JURISDICTION MAY PREFER THE USE OF ONE OF THESETS OF TERMS AND NOT THE OTHER.

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NOTE 2: THE ACTUAL GAS CONCENTRATION CORRESPONDING TO THE LOWERFLAMMABLE LIMIT OF THE SPECIFIC GAS SHALL BE THE VALUE SHOWN FOR THAT GASIN THE LATEST EDITION OF NATIONALLY RECOGNIZED DOCUMENTS, FOR EXAMPLE,NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) 325, FLAMMABILITY CHARACTERIS-TICS OF COMBUSTIBLE GASES OR VAPORS.

1.9.14 Full-scale gas concentration: The gas concentration that equals maximum scale indication.

1.9.15 Gas detection instrument: An assembly of electrical and mechanical components (either a singleintegrated unit or a system comprised of two or more physically separate but interconnected componentparts) which senses the presence of combustible gas and responds by providing an indication, alarm, orother output function.

NOTE: FOR CONVENIENCE, THE TERM INSTRUMENT IS USED AS AN ABBREVIATIONFOR GAS DETECTION INSTRUMENT WITHIN THIS DOCUMENT.

1.9.16 Gas-sensing element (sensor): The primary element in the gas detection system that responds to thepresence of a combustible gas including any reference or compensating unit, where applicable.

1.9.17 Latching alarms: Alarms that once actuated require intentional manual action to reset.

1.9.18 Mobile instrument: A continuously monitoring instrument mounted on a vehicle such as, but notlimited to, a mining machine or fork lift truck.

1.9.19 Portable, continuous-duty instrument: A battery-operated portable or transportable instrumentintended to operate continuously for 8 hours or more.

1.9.20 Portable, continuous-duty, personal instrument: Gas detection instrument refers to a battery-operated, alarm only instrument intended to be operator-worn and to operate continuously for 8 hours ormore.

1.9.21 Portable, intermittent-duty instrument: A battery-operated portable or transportable instrument

intended for operation during periods of only a few minutes at irregular intervals.

1.9.22 Range: The operable concentration region of the instrument or a selected subdivision of that region.

1.9.23 Response conversion data: Information, supplied and explained in the instrument instruction manual,enabling the instrument user to determine the concentration of the gas to be monitored that will producethe same response as a known concentration of another gas used for calibration.

1.9.24 Sample draw: Method by which the atmosphere being monitored is made to flow to the gas sensingelement. This may involve a manual aspirator, an electrical pump or some other means.

1.9.25 Span: The algebraic difference between the upper and lower values of a range.

1.9.26 Stand-alone control unit: Control unit that is utilized with unspecified stand-alone detector head(s).

1.9.27 Stand-alone detector head: Detector head that is utilized with unspecified control apparatus. Suchinstruments are intended to be interfaced to separate control unit, signal processing data acquisition,central monitoring, or other similar systems in which the instrument provides a conditioned electronicsignal or output indication to systems of the aforementioned type that typically process information fromvarious locations and sources including, but not limited to, gas detection instruments.

1.9.28 Stationary instrument: A gas detection instrument intended for permanent installation in a fixedlocation.

1.9.29 Zero: The lower calibration value, normally clean air.

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2. GENERAL REQUIREMENTS

2.1 Review of Documentation

During the initial investigation and prior to physical testing, the manufacturers specifications and details shallbe reviewed to assess the ease and practicality of installation and use.

If any of the manufacturers published claims exceed any of the test condition extremes described in Section 3,the tests shall be conducted under the conditions for which the claims apply.

All claims not tested and verified by FM Approvals as part of the Approval investigation must be clearlyidentified as such in the products installation and operation manual. Alternatively, the manufacturer may includea section or appendix in the manual which clearly itemizes the specifications, features, functions and restrictionsincluded in the FM Approval.

2.2 Markings

2.2.1 In addition to the marking required for general-purpose equipment and by FM Approval Standard 3600,the equipment shall be marked with the information required in this Section, which include the following:

Manufacturers name or trademark and address

Specific model designation and serial number

Instruments ratings (voltage, frequency, current or power, etc.)

Instruments operating ambient temperature range

Hazardous location information

FM Approval Mark. The word APPROVED associated with the Mark may be supplemented as

follows:

APPROVEDFOR PERFORMANCE AND

HAZARDOUS (CLASSIFIED) LOCATIONS

2.2.2 The model or type identification shall correspond to the manufacturers catalog designation and shalluniquely identify the product as Approved.

2.2.3 The FM Approval Mark shall be displayed visibly on the product and/or packaging as appropriate. Themanufacturer shall not use this Mark on any other product unless such product is covered by separateagreement with FM Approvals.

2.2.4 All markings shall be legible and durable.

2.2.5 The marking required in 2.2.6 and 2.2.7 shall appear in a clearly legible, visible, and permanent manneron each gas detection instrument in the following manner, as applicable:

a) For portable instruments, the marking shall appear both on the outside surface of the instrument andon its carrying case, if the latter obscures the marking as required in 2.2.6. and 2.2.7.

b) For stationary instruments, the marking required in 2.2.6 shall appear in a location where it will bevisible after installation and in direct sight during the routine periodic re-calibration and adjustment of setpoint(s).

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NOTE 1: For gas detection instruments that comprise a control unit and remote detector head(s), it issufficient that this marking appear on the control unit only, except if routine re-calibration can beaccomplished entirely by adjustments at the remote detector locations alone, this marking shall appear bothon the control unit and on the remote detector head.

NOTE 2: For modular control units comprising one or more control modules in a common enclosure ormounting assembly, the marking need not be repeated on each module, but may appear as a single markingon the common portion of the assembly.

NOTE 3: Where the design of a stationary control unit is such that there is insufficient space for thismarking to appear on the portion of the unit that is visible after installation (e.g., compact designs for closepanel mounting), the marking required by 2.2.6 is permitted to appear elsewhere on the control unit,provided that a second duplicate label (with an acceptable adhesive) bearing such marking is supplied witheach such control unit (or assembly of control units), together with the instructions that it is to be attachedby the user in a conspicuous location after installation, as close as possible to the control unit.

2.2.6 All gas detection instruments shall be marked:

CAUTION READ AND UNDERSTAND INSTRUCTION MANUAL BEFORE OPERATING ORSERVICING.

The word CAUTION of the foregoing shall be in capital letters at least 3.0 mm high. The balance ofthe wording shall be in capital letters at least 2.5 mm high.

2.2.7 Portable gas detection instruments having scales that indicate gas concentrations only below theflammable range shall be marked:

CAUTION OFF-SCALE READINGS MAY INDICATE EXPLOSIVE CONCENTRATION.

The word CAUTION of the preceding marking shall be in capital letters at least 3.0 mm high. Thebalance of the wording shall be in capital letters at least 2.5 mm high.

2.2.8 Instruments of the type referred to in Section 2.4.5.3 that are not intrinsically safe shall be marked:

CAUTION THIS AREA MUST BE KNOWN TO BE FREE OF FLAMMABLE CONCENTRA-TIONS PRIOR TO OPENING THE ENCLOSURE

The wording shall be in capital letters at least 5.0 mm high and marked in a permanent manner. Themarking shall be conspicuously visible prior to removal of the cover.

2.2.9 Where the design of special features of the instrument requires additional markings or a change in markingrequirements, the additions or revisions are allowed, but the safety and instructional intent of this Section(2.2) must be met.

2.3 Manufacturers Installation and Operation Manuals

2.3.1 Each gas detection instrument shall be provided with an instruction manual, furnished by the manufacturer.The instruction manual shall contain clear and precise instructions for safe and proper operation,installation and periodic servicing of the instrument. The requirements of Sections 2.3.2 and 2.3.3 shall beincluded as applicable. Where the design or special nature of the instrument requires additional instruc-tions that are in contradiction of, or in addition to, the requirements of Sections 2.3.2 and 2.3.3, thisconsideration may take precedence over these requirements. Instructions shall be consistent with themarkings required in Section 2.2.

2.3.2 The following requirements shall be incorporated in the manufacturers instruction and operation manuals:

2.3.2.1 A list of desensitizing or contaminating gases or substances known to the instrument manufacturerwhich may adversely affect proper operation of the instrument. Warning as to the effects, if any,of oxygen-enriched or oxygen-deficient atmospheres shall also be included.

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2.3.2.14 For instruments provided with meters having scales only above or below the flammable range,wording such as:

CAUTION OFF-SCALE READING IN EITHER DIRECTION MAY INDICATE AFLAMMABLE CONCENTRATION

2.3.2.15 The type of calibration gas or vapor mixture to be used. If the instrument is designated to monitorgases other than the one for which it is calibrated, include response conversion data with specificinstructions as to its use.

2.3.2.16 An evaluation procedure to determine the possible sources of malfunction and the correctiveaction to be taken.

2.3.2.17 A listing of consumable or replacement parts, and recommendation of the storage type, envi-ronment and installation instructions.

2.3.2.18 If more than one type of sensor is supplied by the manufacturer, include a list stating the specificgas family or chemically similar gases for each sensor.

2.3.2.19 For instruments which provide measurement outputs (e.g., 4-20 mA signal), the instructionmanual shall provide graphs or other means to indicate the relationship between the input and theoutput.

2.3.3 For stand-alone detector heads, specifications shall be supplied with the instrument that describe therelationship of the gas concentration detected by the instrument, to the corresponding output signal orindication. Such specifications shall be detailed to the extent that the accuracy of the output or signalindication can be verified. As a minimum, the manufacturer shall provide data showing the relationshipbetween the output signal or indication of the instrument and gas concentrations corresponding to 0, 10,25, 50, 75 and 100% of full-scale indication. Full-scale output shall be as specified by the manufacturer.

2.3.4 For stand-alone detector heads and instruments that provide measurement and alarm outputs(e.g., 4-20 mA signal, relay contacts), the following shall appear in the instruction manual:

This Approval does not include or imply Approval of apparatus to which the subject instrumentation maybe connected. In order to maintain an FM Approved system, the apparatus to which this instrument isconnected, must also be Approved by FM Approvals.

2.3.5 For stand-alone control units, the following shall appear in the instruction manual:

This Approval does not include or imply Approval of gas detector heads or other apparatus to which thesubject instrument may connected. In order to maintain an FM Approved system, the measurement inputsignal to which this instrument is connected must also be FM Approved.

2.3.6 Communication options

For instruments providing communications options that are not included in the Approval examination butwhich comply with requirements of Section 3.3 (NOTE 2), the following shall appear in the instructionmanual:

As part of this Approval, it was verified that optional communication functions of this gas detectioninstrument while operating at the maximum transaction rate do not adversely affect the gas detection

operation and functions of the instrument. This Approval, however, does not include or imply Approvalof the communications protocol or functions provided by the software of this instrument or of thecommunications apparatus or software connected to this instrument.

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2.4 Construction and Functions

2.4.1 General requirements

2.4.1.1 Gas detection instruments, their components, or remote detector heads specifically intended for

use in the presence of corrosive vapors or gases, or that may produce corrosive by-products as aresult of catalytic oxidation or other chemical process, shall be constructed of materials resistantto or suitably protected against corrosion.

2.4.1.2 Portable instruments of the sample-draw type shall include the necessary sample-pumpingmechanism.

2.4.2 Meters, indicators and outputs

2.4.2.1 Stationary and continuous-duty portable gas detection instruments having an integral meter orindicator to indicate gas concentrations shall employ a meter having sufficient resolution to permitmeasurement with the precision required for the tests of Section 3.

2.4.2.2 Operational characteristics of nonlinear meters or indicators, when used, shall be stated in theinstruction manual.

2.4.2.3 Continuous-duty portable instruments of the sample-draw type shall incorporate a device toindicate adequate flow, except that such an indicating device may be omitted provided that theinstruction manual contains detailed instructions as required by Section 2.3.2.10.

2.4.2.4 A means shall be provided to alert the user that a gas concentration in excess of the measuringrange of the instrument has been detected.

2.4.3 Alarm or output function

2.4.3.1 Alarm devices, output contacts, or signal outputs (if provided as part of stationary instruments orcontinuous-duty portable instruments and intended to indicate a potentially flammable gas con-centration) shall be of a latching-type requiring a deliberate manual action to reset. If two or moreset or alarm positions are provided, the lower may be non-latching.

NOTE: The latching requirement may be omitted or a defeating option permitted only when a

clear and prominent statement in the instruction manual specifies that the instrument shall beconnected to an auxiliary system which accomplishes the same purposes as latching

2.4.3.2 Alarm devices or signals of the non-adjustable alarm set-point type shall be set to operate at a gasconcentration not higher than 60% of the lower flammable limit. For alarm devices or signals ofthe adjustable alarm set-point type, the means for adjustment shall not be capable of being sethigher than 60% of the lower flammable limit.

2.4.4 Trouble signals

2.4.4.1 A stationary or mobile gas detection instrument shall provide for a signal transfer or contacttransfer to produce a trouble signal if any of the following conditions occur:

a) instrument power failure;

b) loss of continuity in any one or more conductors to any remote detector head;

c) loss of continuity of any gas-sensing element; or

d) down scale indication (below zero) equivalent to 10% nominal LFL or more.

Such signal or contact transfer shall be independent of any other alarm or shutdown signal orcontact transfer.

2.4.4.2 Stationary and mobile sample-draw-type gas detection instruments shall be provided with flow-proving devices (either integral or non-integral), which shall produce a trouble signal in the formof a contact transfer or signal transfer if a loss of flow occurs.

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2.4.4.3 Continuous-duty, portable gas detection instruments shall be provided with an audible or visibleindication of low battery condition, and the nature and purpose of either shall be clearly explainedin the instruction manual.

2.4.4.4 If the manufacturer provides a mechanism that will disable alarm outputs for maintenance or

calibration purposes, that mechanism shall either trip the fault signal and produce a visual indi-cation or provide a similar independent set of signals.

2.4.5 Controls and adjustments

2.4.5.1 All portable gas detection instruments shall be provided with means for facilitating calibrationchecks and adjustments as required.

2.4.5.2 Calibration and alarm(s) setting shall be designed to discourage unauthorized or inadvertentinterference with the setting(s). Examples of acceptable methods include mechanical devices (suchas a cover requiring the use of a tool) and passwords (input by authorized users).

2.4.5.3 Fixed instruments housed in explosionproof or pressurized enclosures shall have all controls fornormal operation accessible from outside the enclosures. The controls for routine calibration maybe inside the enclosure, provided all of the following requirements are met:

a) The enclosure has a cover that can be readily opened or closed and that does not requireremoval and replacement of bolts or other securing devices in order to open and re-close theenclosure; and

b) All adjustments, switches, or controls that may be deliberately or accidentally operated duringthe calibration procedure shall involve only circuits meeting requirements for nonincendive cir-cuits: and

c) All un-insulated parts of circuits exceeding 30 V rms or 42.4 V peak or 60 Vdc and of circuits30 V rms or less that are not Class 2 power limited (as defined by Article 725 of the NationalElectrical Code ANSI/NFPA 70) shall be protected from accidental contact by appropriatemechanical guards or partitions; and

d) The enclosure shall be marked as described in Section 2.2.8.

2.4.5.4 Measurement indications and output signals (e.g., current loop, voltage, etc.) of stand-alone

detector heads must have the ability to be calibrated for zero and span, with or without thepresence of a control unit (use of simulated control unit input is satisfactory).

2.4.5.5 Measurement input signals (e.g., current loop, voltage, etc.) and indications of stand-alone controlunits or systems must have the ability to be calibrated for zero and span, with or without thepresence of a detector head (use of simulated detector head output is satisfactory).

2.4.5.6 Auxiliary measurement output signals (e.g., 4-20 mA, voltage, etc.) provided with detector headsor control units must have the ability to be individually calibrated for zero and span.

2.4.6 Batteries

2.4.6.1 Continuous-duty portable gas detection instruments with fresh or fully charged batteries shall becapable of continuous non-alarming operation for a period of at least 8 h without replacing orrecharging batteries.

2.4.6.2 Intermittent-duty portable gas detection instruments with fresh or fully charged batteries shall becapable of non-alarming operation at a duty cycle of 10 minutes (min) On and 10 min Offfor a period of 8 h (total cumulative On time of 4 hours) without replacing or recharging thebatteries. If the instrument is provided with a switch that must be manually held in the Onposition for the duration of the measurement, the duty cycle shall be reduced to 2 min On and18 min Off for a period of 8 h (total cumulative On time of 48 min).

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2.4.7 Enclosures

2.4.7.1 Instrument enclosures, including associated accessories, intended for outdoor use as specified bythe manufacturer shall be tested for such locations.

2.4.7.2 All parts of the instrument subjected to the combustible gas atmosphere to be monitored shall be

suitable for that location.

2.4.7.3 The effects of the tests required to verify the instruments suitability for specified locations (dust,rain, hosedown, corrosion tests, etc.) shall be considered as part of performance tests in Section 3.

2.5 Test Equipment Calibration

All examinations and tests performed in evaluation to this Standard shall use calibrated measuring instrumentstraceable and certified to acceptable national standards.

3. PERFORMANCE REQUIREMENTS

3.1 General

a) The tests required in this section are in addition to the requirements of applicable standards referred to inSection 1.8.

NOTE: Examination and tests required in applicable standards in Section 1.8 shall be satisfactorily completedprior to the start of tests required in this section and any modifications or changes resulting from those

requirements shall be incorporated in the instruments under test.

b) The instruments tested shall be fully representative of instruments intended for commercial production.

c) Unwarranted or false alarms shall be considered failure of the tests described below.

d) All output indications and signals, not directly scaled in %LFL, shall be converted to the applicable %LFLconcentration readings. The converted value(s) shall be used for determination of all deviations from standardrequirements. For example, the conversion of a 4-20mA output to %LFL concentration shall be performed usingthe following formula:

Im

4Measurement (%LFL) = Full-scale

16[ ]Where: I

mis the measured 4-20 mA loop current in mA

Full-scale is the instruments maximum range value

e) Tests shall be conducted with all equipment installed as intended for use.

f) For multiple gas sensing instruments, all unwarranted (false) alarms which require re-setting, re-adjusting,etc., to continue combustible gas detection tests shall be considered a failure.

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3.2 Samples and Sequence

One previously untested instrument including all optional or accessory parts to be used on the final Approvedinstrument shall be subjected to all tests applicable to that instrument type as described in the following sections.The instrument tested shall be fully representative of instruments intended for commercial production. The sameinstrument shall be subjected to all tests applicable to that type of instrument described in Sections 3.6 through3.19. The sequence of tests shall correspond to the order of these sections.

EXCEPTION: The tests described in Sections 3.11 through 3.16 (i.e., temperature, step change, humidity, airvelocity, supply voltage, and EMI) may be performed at any time after the test described in Section 3.10, butbefore the test described in Section 3.17.

NOTE: For stationary or continuous-duty instruments of the sample-draw-type, air velocity variation testingmay not be applicable.

3.3 Preparation of instrument

The instrument selected for testing shall be prepared as if for actual service, including all necessary intercon-nections and initial adjustments, in accordance with the manufacturer s instruction manual.

NOTE 1: For instruments having remote detector heads, all tests shall be performed with resistors (withtemperature coefficients similar to those of the recommended interconnecting conductors) connected in thedetector circuit to simulate the maximum line resistance specified by the instrument manufacturer, except whereminimum line resistance offers a more stringent test.

NOTE 2: For instruments having serial or parallel communications options, tests in Sections 3.9, 3.10, 3.12,3.15, 3.16 and 3.18 shall be performed with all communications ports connected to apparatus which initiates themaximum transaction rate and activity level specified by the instrument manufacturer. Special apparatus may beused to simulate the communications activity and must be provided by the manufacturer. (See Section 2.3.6)

NOTE 3: For instruments that are part of a system evaluated for Approval, tests in Sections 3.9, 3.10, 3.12, 3.15,

3.16 and 3.18 shall be performed with the maximum system communications transaction rate and activity levelwhich would result from the largest and most complex system configuration. Special apparatus may be used tosimulate the system activity and must be provided by the manufacturer.

3.4 Conditions for test and test area

3.4.1 Voltage

Except as otherwise indicated herein, all tests shall be performed at the nominal system voltage andfrequency marked on the equipment, or, if applicable, with fresh or fully charged batteries.

3.4.2 Ambient temperature

Except as otherwise indicated herein, tests may be performed at conveniently available room ambienttemperatures in the range of 18C to 30C.

3.4.3 Humidity

Except as otherwise indicated herein, tests may be performed in ambient air having a relative humidity ofany convenient value in the range of 30 to 70%.

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3.4.4 Room air circulation

Except as otherwise indicated herein, tests are to be performed in relatively still air (not more than 1 meterper second [m/s]) except for those currents that may be induced by convection due to the natural heatingof the equipment under test or caused by air-moving devices that are part of the equipment under test. It

should be noted that the output indication may differ under conditions of a stagnant sample (samplevelocities of 0.1 m/s or less).

3.4.5 Removal of parts

For purposes of the tests in Sections 3.7 through 3.18, where reference is made to exposing the sensinghead to specified gas mixtures or to other specified conditions, in the case of remote detector heads, theentire head, including all normally attached diffusion devices or protective mechanical parts, shall be soexposed.

3.4.6 Multiple detector heads

For stationary, mobile, or continuous-duty portable gas detection instruments intended to be used withmore than one remote detector head, for tests that call for the exposure of the remote detector head to aspecified test gas or other specified set of conditions, only one detector head shall be so exposed. Dummy

electrical loads (e.g., fixed resistors) may be substituted for additional heads but if additional heads areused, all other heads shall be exposed to normal, clean air and normal conditions for tests as described inSections 3.4.2 through 3.4.4.

3.4.7 Re-calibration or adjustment

The instrument under test may be adjusted or re-calibrated prior to the start of each test described inSections 3.8 and 3.10 through 3.18. However, no further adjustments or re-calibration shall be carried outfor the duration of that test except where specifically permitted by the particular test procedure.

3.4.8 Stabilization time

For the tests in Sections 3.11, 3.13, 3.14, and 3.15, each time the instrument is subjected to a different testcondition, the instrument shall be allowed to stabilize under these new conditions (see note below) beforemeasurements are taken for comparison purposes.

NOTE: An instrument shall be considered to be stabilized when three successive observations of theindication taken at 5-min intervals indicate no significant change.

3.4.9 Instruments having alarms only

Instruments having alarms only do not have any meter or other output indication that can be comparedbefore and after the tests described in Section 3. For purpose of the test, the alarm set point shall be setat 20% LFL and a tolerance of 5% LFL applied for all tests.

3.4.10 Stand-alone gas detection instruments for use with separate control units

3.4.10.1 General

Section 3.4.10 includes instruments that provide a conditioned electronic signal or output

indication intended to be used with separate signal processing, data acquisition, central moni-toring or other similar systems which typically process information from various locations andsources including, but not limited to, gas detection instrumentation.

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3.4.10.2 Transfer function specification

A specification shall be supplied with the instrument that describes the relationship of the gasconcentration, detected by the instrument, to the corresponding output signal or indication(transfer function). Such specification shall be detailed to the extent that the accuracy of this

transfer function can be verified. As a minimum, the manufacturer shall provide data showingthe relationship between the output signal and the gas concentrations corresponding to 0, 10%,25%, 50%, 75% and 100% of full scale output indication. Full scale output shall also be asspecified by the manufacturer.

3.4.10.3 Provision for transfer function verification

Where necessary, equipment shall be provided by the manufacturer to interpret the output signalor indication which will enable the accuracy of the transfer function to be verified.

3.4.11 Separate control units for use with stand-alone gas detection instruments

3.4.11.1 General

Section 3.4.11 includes those instruments to be used with stand-alone gas detection instruments(as defined in Section 3.4.10) to complete a performance evaluated combustible gas detection

system.

3.4.11.2 Tests

The control units shall be tested to the requirements of Sections 3.6, 3.8, 3.9, 3.10, 3.11, 3.15,3.16 and 3.19 using the parameters of the transfer function pertinent to the specific type of gasdetector.

3.5 Selectable gas/range instruments

3.5.1 For instruments having more than one selectable range or scale for the same gas, the tests in Sections 3.8and 3.10 through 3.18 shall be performed with the instrument operating at both the least and most sensitiveranges, except that if the most sensitive range has a full scale equal to or less than 25% of the LFL, the

performance shall be that specified by the manufacturer in the instruction manual. If the manufacturer doesnot state the performance characteristics of the most sensitive scale where it is 25% of LFL or less, theperformance shall be the same as for the least sensitive range.

3.5.2 For instruments having selectable ranges employing different detecting means, all of these tests shall beperformed on each range.

3.5.3 For instruments having specific ranges or scales for different gases:

a) After only one vibration test performed per Section 3.8.2, the tests in Section 3.8.3 shall be repeatedat each selectable range for each gas.

b) The tests in Sections 3.11 through 3.19 shall be repeated at each selectable range for each gas.

3.6 Un-powered preconditioning storage

Prior to tests in Sections 3.9 through 3.19, all parts of the combustible gas detection instrument shall be exposedsequentially to the following conditions:

a) Temperature of -35C for 24 h

b) Ambient temperature and humidity for at least 24 h

c) Temperature of +55C for 24 h

d) Ambient temperature and humidity for at least 24 h

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3.7 Drop test

3.7.1 This test is applicable only to portable instruments

3.7.2 While in the operating mode, the instrument (less any removable case) shall be released from a height of1 m above a concrete surface and allowed to free-fall.

3.7.3 The test required in Section 3.7.2 shall be performed three separate times, each time released with adifferent surface, edge or corner of the instrument facing down at the time of release.

3.7.4 The instrument shall be considered to fail this test if it is inoperative after the test.

NOTE: Failures resulting from this test may not become apparent until subsequent tests are conducted.

3.7.5 For the tests in Section 3.7, multi-range instruments need to be tested only on one range.

3.8 Vibration

3.8.1 Apparatus

The vibration test machine shall consist of a vibrating table, capable of producing a vibration of variablefrequency and variable constant excursion (or variable constant acceleration peak) with the instrumentunder test mounted in place, as required by the test procedure described in Section 3.8.2.

3.8.2 Procedures

The remote detector head, the control unit, and all portable instruments shall be mounted on the vibrationtest machine and vibrated successively in each of three mutually perpendicular directions, respectivelyparallel to the edges of the instrument. The instrument shall be mounted on the vibration table in the samemanner and position as intended for service using any resilient mounts, carrier, or holding devices that areprovided as a standard part of the instrument.

The instrument shall be vibrated over a frequency range of 10 Hz to 30 Hz at a total excursion of 0.5 mmfor a period of 1 hour in each of three mutually perpendicular directions. The rate of change of frequencyshall not exceed 100 Hz/min. This test procedure shall apply to the remote detector head, the control unit,and all portable instruments.

3.8.3 Test criteria

The instruments shall not give any false alarms; there shall be no loose components or damage to theenclosure that could cause a hazard, and, when tested with clean air and the initial calibration mixture, thereading shall be accurate within 5% of full-scale gas concentration after this test. In lieu of the test criteriaabove, instruments incorporating alarms only shall be actuated by a 24- to 26-% LFL test gas mixture butnot be actuated by a 14- to 16-% LFL test gas mixture after this test.

3.9 Calibration

The instrument shall be calibrated for testing in accordance with this standard using manufacturer s calibrationfixture and specified calibration procedures. The calibration gas shall be a nominal 50% of the instrumentsfull-scale gas concentration. The combustible gas to be used shall be as follows:

Methane for instruments intended for sensing methane specifically, or intended for general-purposecombustible gas detection (including detection of methane)

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Propane for instruments intended for general-purpose combustible gas detection that excludes methane

The actual specific gas or a representative gas for instruments intended for sensing a specific combustiblegas or a specific family of chemically similar combustible gases

NOTE 1: When instruments can be used for detecting more than one combustible gas by changing only thegas-sensing element, then only those tests as described in Sections 3.8, 3.9, 3.10, 3.11, 3.12, 3.13, 3.14, 3.17, and3.18 need to be repeated for the second and subsequent gases. Methane shall be tested first if a methane-sensing element is supplied by the manufacturer.

NOTE 2: Unless otherwise indicated herein, the manufacturers calibration device is to be used to supply thegas mixture to the gas-sensing element for the tests described in the paragraphs that follow. However, theinstruments response utilizing this method and the instruments intended method of gas monitoring, if different,shall first be established.

NOTE 3: Gas mixtures having the same concentrations as those used for tests in Section 3.9 are used for variousother tests described in the paragraphs that follow. For ease of reference, such gas mixtures will hereafter bereferred to simply as the initial calibration gas mixture.

3.10 Accuracy

3.10.1 All test gas concentrations shall be known to a tolerance of 2% of %LFL value.

3.10.2 The sensing head shall be exposed to five gas concentrations falling in each of the following ranges: 9to 11%, 24 to 26%, 49 to 51%, 74 to 76%, and 98 to 100% of the full-scale gas concentration. In eachcase, the concentration indicated by the meter or output signal shall not vary from the known test gasconcentration by more than 3% of full-scale gas concentration or 10% of applied gas concentration,whichever is greater.

NOTE: As part of this test, alarm functions shall be verified to actuate within 5%LFL when respec-tive set-point values are crossed. Set-points may be set at convenient values over the instrument range

3.10.3 For instruments having alarms only, testing shall verify that each alarm 1) actuates on exposure togas-air mixtures whose concentrations are at the upper tolerance limit for alarm actuation; and 2) doesnot actuate on exposure to mixtures whose concentrations are below the lower tolerance limit. (SeeSection 3.4.9.)

3.11 Temperature

This test shall be performed in a temperature chamber with the capability of holding the apparatus at thespecified temperature within 2C. When the apparatus (or the portion under test) has reached the temperaturespecified in this section, as appropriate, the gas sensing element (sensor) shall be exposed sequentially to airand the standard test gas, which shall be at the same temperature as the atmosphere in the test chamber. Thedew point of the air or the standard test gas shall be below the lowest temperature of the test chamber and kept

constant during the test.

The variation of the indication from that at +20C, over the specified temperature ranges, shall not exceed thefollowing:

a) for portable or transportable apparatus where the control unit and sensor are used in the same generalenvironment, the variation over the temperature range -10C to +40C shall not exceed 5% of the measuringrange or 10% of the indication, whichever is greater. Tests shall be carried out at temperatures of -10C, +20Cand +40C;

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b) for fixed apparatus with remote sensors or detector heads, where the control unit and the detector head orsensor are not used in the same general environment, the following temperatures shall be applied:

1) Sensors or detector heads

With the control unit under normal ambient test conditions, the sensor or detector head shall be tested in

air and in the standard test gas at -25C and +55C. The variation shall not exceed 10% of the measuringrange or 20% of the indication, whichever is greater.

2) Control units

With the sensor or detector head under normal ambient test conditions, the variation at +5 C and +55Cshall not exceed 5% of the measuring range or 10% of the indication, whichever is greater;

c) for fixed apparatus with sensors or detector heads and control units in the same general environment, thevariation at -10C and +55C shall not exceed 5% of the measuring range or 15% of the indication,whichever is greater.

3.12 Step change response

3.12.1 Beginning in clean air, the gas-sensing element shall be suddenly exposed to a prepared mixture ofgas-in-air having a concentration corresponding to 100% of full-scale gas concentration. From theinstant of exposure to this gas mixture, the instrument shall respond to provide an indication of 60% offull-scale gas concentration within 12 s.

NOTE: For sample-draw-type instruments, the above time does not include the transport time requiredfor the gas sample to reach the instrument from a remote sampling point. For manually aspiratedinstruments without a sampling line, the time is to be measured from the time of starting the first manualaspiration.

3.12.2 When instruments incorporating alarms only are tested, and when optional readout capability is notoffered, the following clause shall be substituted for Section 3.12.1:

Beginning in clean air, the gas-sensing element shall be suddenly exposed to a 100% LFL gas-air

mixture. An alarm set to 20% LFL of the mixture shall respond within 10 s of exposure to the stepchange.

3.13 Humidity variation

The instrument shall first be calibrated; then the gas-sensing element shall be exposed to the initial calibrationgas mixture at a relative humidity of 50% for 2 h. Next the gas sensing element shall be exposed for 2 h to thecalibration gas mixture to which water vapor has been added to raise the relative humidity to a final value of90%. The sensing head shall then be exposed for 2 h to the calibration gas mixture having a relative humidityof 10%. The meter or output indications during these exposures shall not vary from the 50% relative humidityexposure indication by more than 10% of full-scale concentration.

For instruments incorporating alarms only, the alarm shall not be actuated by 14 to 16% LFL test gas, but shallbe actuated by 24 to 26% LFL test gas while exposed to both humidity extremes.

NOTE: Relative humidity values are to be accurate within 5 relative humidity percentage points.

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3.14 Air velocity variation

3.14.1 The instrument shall be calibrated first with the gas-sensing element exposed to a still (ref.Section 4.4.4) mixture of the initial calibration gas. It shall then be exposed to the initial calibration gasmixture in motion so as to impinge on the gas-sensing element with a velocity of 5 0.5 m/s. The meteror output indication during exposures to the mixture in motion shall not vary from that observed duringexposure to the still gas mixture by more than +10% or -5% of full-scale gas concentration in theorientation that causes the greatest deviation.

3.14.2 For instruments incorporating alarms only, the alarm shall not be actuated on 14 to 16% LFL test gasbut shall be actuated on 24 to 26% LFL test gas while exposed to the mixture in motion 5 0.5 m/s inall orientations.

3.15 Supply voltage variation

3.15.1 For gas detection instruments intended for operation on ac power supply systems and with the gas-sensing element exposed to the initial calibration gas mixture (see Section 3.9), the supply voltage shall

first be decreased to 85% of nominal line voltage and then increased to 110% of nominal line voltage.

NOTE: The method of causing these step changes in voltage shall simulate the effect of a heavy loadbeing added to or removed from the source of supply; i.e., there shall be no actual interruption of thevoltage supply during the voltage transition.

The variation in the meter or output indication from actual concentration shall not exceed 2% offull-scale gas concentration. (See Section 3.4.8.)

3.15.2 For ac-powered instruments, incorrect functions shall not occur when the primary power is applied orremoved.

NOTE: For test purposes, gas detection instruments intended for operation from an external ac powersource shall be subjected to momentary power interruptions of approximately 0.5 s and 5 s.

During this test, the detector head shall be exposed to clean air (see Sections 3.4.2 to 3.4.4), and alarms

set in the same manner as for Section 3.15.3.

3.15.3 Gas detection instruments intended for operation from an external dc power source shall be subjectedto a step-change in supply voltage from nominal to 122.5% of nominal voltage, and from nominal to87.5% of nominal voltage. During this test, the sensing head shall be exposed to clean air. (See Sections3.4.2 through 3.4.4.) Adjustable alarms shall be set to operate at 10% of the LFL or 10% of full-scaleconcentration, whichever is lower, or at the lowest possible setting if this setting is greater. As a resultof this test, there shall be no instrument malfunction or actuation of the alarms that would falselyindicate the presence of combustible gas. The test shall be repeated with the sensing head exposed to90% of full scale concentration. As a result of this test, there shall be no malfunction or interruption ofthe instrument alarms.

NOTE: The method of causing these step changes in voltage shall be such as to simulate the effect ofa heavy load being added to or removed from the source of supply; i.e., there shall be no actual

interruption of the voltage supply during the voltage transition.

3.15.4 For self-contained battery-operated instruments, the voltage variation shall correspond to the maximumterminal voltage of a fresh or fully charged battery(ies) and the minimum recommended operatingvoltage of that (those) battery(ies), as determined by a built-in battery-condition indicator. Intermittent-duty portable instruments having provision for adjustment to compensate for battery voltage declinemay be so adjusted. (See Section 3.4.8.)

3.15.5 For instruments incorporating alarms only, the alarm shall be actuated by 24 to 26% LFL test gas, butnot 14 to 16% LFL test gas, while exposed to both voltage variation extremes.

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3.16 Electromagnetic Interference (EMI)

Following satisfactory completion of all the applicable tests of the preceding clauses, the stationary or mobileinstrument (including sensor, electronics, and interconnecting wiring) shall be subjected 1) while in an ener-gized (operating) mode and 2) while in the position of normal calibration, to electromagnetic energy in thefrequency ranges of 150 to 170 MHZ and 450 to 470 MHZ, using frequency-modulated portable radiotransmitters (5 W input to the final amplifier) at a distance of 1 m away from the instrument (i.e., its sensor,electronics, and interconnecting wiring).

Tests shall be conducted for both items 1) and 2) above, using a randomly selected frequency within each ofthe two frequency ranges. These tests shall not cause the instrument to produce output changes of more than10% of full scale or result in an incorrect instrument function.

Tests should be conducted following the manufacturers suggestions concerning wiring, shielding, and instal-lation techniques as they pertain to electromagnetic interference.

3.17 Long-term stability

NOTE: Repeat applicable accuracy tests (Section 3.10) before performing the test under this section.

3.17.1 Stationary instruments

The gas-sensing element shall be consecutively subjected to the following sets of conditions for theperiods stated (Section 3.4.7):

a) Clean air at ambient temperature and humidity for six continuous days. (See Sections 3.4.2and 3.4.3).

b) At the beginning of the seventh day, expose the gas-sensing element to the initial calibration gasmixture for a period of 24 h. Within 5 min after start of the test, the indicated concentration shall benoted and shall not deviate from the actual calibration gas concentration by more than 10% of full scalefor the remainder of the 24 h.

c) Repeat a) and b) a total of four consecutive times (total of 28 days). Just prior to the end of the 14th

and 28th days, while the gas-sensing element is still exposed to the initial calibration gas mixture, theindicated concentration shall be noted and shall not deviate from the actual calibration gas concentrationby more than 10% of full scale.

NOTE: Following the deviation check at the end of the 14th and 28th days, the instrument may bezeroed and re-calibrated.

d) Expose the gas-sensing element to clean air at ambient temperature and humidity for 24 h. At the endof this period, the gas-sensing element shall be exposed to the initial calibration gas mixture, and theindicated concentration observed after 5 min shall not deviate from the actual gas concentration by morethan 10% of full scale.

NOTE: Following the deviation check at the end of d), the instrument may be zeroed and re-calibratedprior to the final accuracy test of e).

e) Immediately after completing d) (total elapsed time for tests a) through d) is 29 days), repeat theaccuracy test procedure in Section 4.10, except that the maximum allowable deviation shall not varyfrom the known test gas concentration by more than 4% full-scale gas concentration or 12% of theapplied gas concentration, whichever is greater.

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3.17.2 Continuous-duty portable instruments

The instrument shall be consecutively subjected to the following sets of conditions for the periods stated(see Section 3.4.7):

a) The gas-sensing element shall be exposed to clean air at ambient temperature and humidity for six

cycles of operation, each cycle consisting of 8 h with the instrument On, followed by 16 h with theinstrument Off (total elapsed time of 24 h per cycle).

b) At the beginning of the seventh day, the gas-sensing element shall be exposed to the initial cali-bration gas mixture for a period of 8 h with the instrument On, following which it shall be exposedto clean air at ambient temperature and humidity with the instrument Off for a period of 16 h. Theindicated concentration shall be noted over a period of 5 min and shall not deviate from the actualcalibration gas concentration by more than 10% of full scale.

c) Repeat a) and b) a total of four consecutive times (total elapsed time of 28 days).

d) The gas-sensing element shall be subjected to clean air at normal ambient temperature and normalhumidity for an additional period of 6 h with the instrument On.

e) Immediately after completing d) (total elapsed time for test a) through d) is 28 days and 6 h), repeataccuracy test procedure of 3.10, except that the maximum allowable deviation shall not vary from theknown test gas concentration by more than 4% of full-scale gas concentration or 12% of the appliedgas concentration, whichever is greater.

1) In lieu of the accuracy tests above, instruments incorporating alarms only shall not be actuatedby exposure to a 14 to 16% LFL test gas mixture and shall be actuated by a 24 to 26% LFL testgas mixture after completing d).

2) The test described in e) shall be performed immediately after the 6 h test of (d) and shall becompleted in not more than 2 h so that the total elapsed instrument On time for tests d) and e)does not total more than 8 h.

NOTE 1: For instruments using replaceable (non-rechargeable) batteries, a suitable dc power supplymay be used or fresh batteries may be installed at the start of each of the 8 h On periods, except thatthe actual batteries specified for the instrument shall be used for the first 8 h of a).

NOTE 2: For instruments using rechargeable batteries, the same rechargeable battery shall be used forthe entire test sequence of a). A suitable dc power supply may be used for the remainder of the test.

NOTE 3: Zero and span adjustments are permitted prior to each stipulated 8 h On period.

3.17.3 Intermittent-duty portable instruments

Intermittent-duty portable instruments provided with a switch that must be manually held in the Onposition shall be subjected to the same test sequence and evaluation as described in Section 4.17.2,except that each 8-h On period shall consist of 24 cycles of 10 min On and 10 min Off.

NOTE 1: Manually aspirated-type instruments shall be aspirated continuously during each 10-minOn period; alternatively, a vacuum pump having an equivalent flow may be utilized.

NOTE 2: Instruments having provisions for voltage adjustments to compensate for battery voltagedecline shall be adjusted as necessary during the above tests, including just prior to the final evaluation.

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3.18 Flooding with undiluted gas

3.18.1 The gas-sensing element of instruments other than the manually aspirated type shall be subjected to astep change in gas concentration from 0% (clean air) to 100% gas-by-volume. The instrument shallproduce an output indication corresponding to a concentration of at least 60% of the lower flammablelimit or to full-scale concentration, whichever is lower, within 10 s of exposure to the 100% gas-by-volume. (See Section 2.3.2.2)

3.18.2 Manually aspirated instruments shall be subjected to a test whereby, using the shortest possible sampletube, they are aspirated at the rate that is recommended by the manufacturer with the sample inletconnected to a source of 100% gas by volume. During this test, the instrument shall produce an outputindication corresponding to at least 60% of the lower flammable limit or to full scale, whichever islower, within 10 seconds.

NOTE 1: For sample-draw instruments of other than the manually aspirated type, the times givenabove do not include the transport time required for the gas sample to reach the instrument from asampling point.

NOTE 2: For detection of vapors whose properties are such that the concentration, due to its vapor

pressure properties, cannot be obtained, another appropriate gas may be used for the tests in Sections3.18.1 and 3.18.2.

3.18.3 During the tests of Sections 3.18.1 and 3.18.2, if the instrument is provided with audible or visible alarmsignal devices or alarm contacts, these shall be set to the 60% of lower flammable limit set point or tothe highest adjustable set point, whichever is lower, and shall be actuated as a result of these tests.

3.18.4 When instruments incorporating alarms only (without an optional readout capability) are tested, thefollowing shall be substituted:

Beginning with the gas-sensing element in clean air, it shall be subjected to a step change in gasconcentration from clean air to 100% gas-by-volume. An alarm set to 20% LFL of the mixture shallrespond within 10 s of exposure to the undiluted flooding condition.

3.19 Additional Tests

Additional tests may be required, at the discretion of FM Approvals, depending on design features and resultsof any foregoing tests.

A re-test following a failure shall be acceptable only at the discretion of FM Approvals and with a technicaljustification of the conditions or reasons for failure.

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4. OPERATIONS REQUIREMENTS

4.1 Demonstrated Quality Control Program

4.1.1 A Quality Control Program is required to assure that each subsequent unit produced by the manufacturershall present the same quality and reliability as the specific samples examined. Design quality,conformance to design, and performance are the areas of primary concern.

Design quality is determined during the examination and tests.

Conformance to design is verified by control of quality on the following areas:

existence of corporate quality control guidelines

incoming quality assurance, including testing

in-process quality assurance, including testing

final inspection and tests

equipment calibration

drawing and change control

packaging and shipping.

Quality of performance is determined by field performance and by re-examination and test.

4.1.2 The manufacturer shall establish a system of product configuration control to prevent unauthorizedchanges, including, as appropriate:

engineering drawings

engineering change requests

engineering orders

change notices.

These shall be executed in conformance with a written policy and detailed procedures. Records of allrevisions to all Approved products shall be kept.

4.1.3. Changes to critical documents, identified in the Approval Report, must be reported to, and authorized by,FM Approvals prior to implementation for production. The manufacturer shall assign an appropriateperson or group to be responsible to obtain FM Approvals authorization of all changes applicable toApproved products. FM Approvals Form 797, Approved Product Revision Report or Address/ ContactChange Notice is provided to notify FM Approvals of pending changes.

4.2 Facilities and Procedures Audit (F&PA)

4.2.1 An inspection of the product manufacturing facility shall be part of the Approval investigation. Its purposeshall be to determine that the equipment, procedures, and manufacturers controls are properly maintainedto produce a product of the same design quality as originally verified.

4.2.2 Unannounced follow-up inspections shall be conducted to assure continued quality control and productuniformity.

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Product label drawing(s) showing all required marking information. The label drawing should showproposed artwork indicating the manufacturers name, address, model and serial numbers, equipmentratings, warning markings, and the FM Approval mark.

Protective Grounding Detail drawing(s) showing the method of protective grounding provided, including

location, size, and marking.

Documentation Control Specification showing proposed method of controlling documents which may beidentified as Critical Documents by FM Approvals. These drawings will be identified by FM Approvalsat the conclusion of the Approval program. FM Approvals must be notified of changes to these docu-ments via Form 797, Approved Product Revision Report.

Any Approval documents from other Nationally Recognized Testing Laboratories (NRTLs) or NationalCertification Bodies (NCBs) needed to support an FM Approval process, i.e., component recognitions,Listing reports, Certification reports, IEC/CB Scheme reports, IEC/CCA reports, etc.

A-2 Requirements for Samples for Examination

A-2.1 Following authorization of an Approval examination, the manufacturer will be required to submit samplesfor examination and testing based on requirements to be determined by FM Approvals during the reviewof the preliminary information.

A-2.2 Requirements for samples may vary depending on design features, results of prior or similar testing, andresults of any foregoing tests.

A-2.3 The manufacturer shall submit samples representative of production. Any decision to use data generatedutilizing prototypes is at the discretion of FM Approvals.

A-2.4 It is the manufacturers responsibility to provide any necessary test fixtures, such as those which may berequired to evaluate the subject apparatus.

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APPENDIX B

UNITS OF MEASUREMENT

LENGTH: mm millimeters

inches = mm 0.03937

m meters

feet = m 3.2808

PRESSURE: kPa kilopascals

psi (pounds per square inch) = kPa 0.14504

bar bar

kPa = 100 bar

psi = bar 14.503

TEMPERATURE: C degrees Celsius

F (degree Fahrenheit) = (C 9/5) + 32

FLOW RATE: lpm liters per minute

ft3/min (cubic feet per minute) = lpm 0.035315

VELOCITY: m/s meters per second

ft/s (feet per second) = m/s 3.2808

6310, 6320 January 2001

FM 6310, 6320 Combustible Gas Detectors

Documents

Transcript of FM 6310, 6320 Combustible Gas Detectors