crh2013-WatsonTom (ASHRAE)

International Refrigerant

Standards and their Influence

on the Global HVAC Industry

and Refrigerant Replacement

Tom Watson, P.E.

Fellow ASHRAE, Life Member

President ASHRAE

Issues

• Choosing a refrigerant requires more knowledge

• Environmental concerns due to:

– ODP (ozone depleting potential)

– GWP (global warming potential)

– energy efficiency

– LCCP (life cycle climate performance

• Safety standards being updated to reflect

increasing interest in flammable/mildly flammable

working fluids

Standards

• Flammability/toxicity requirements covered by ASHRAE

safety standards 15 and 34 and their international

equivalents (ISO 5149, ISO 817)

• Other organizations adopt ASHRAE technical

requirements into codes and regulations

• Major ASHRAE standards dealing with refrigerants are:

– Standard 34, Designation and Safety Classification of Refrigerants

– Standard 15, Safety Standard for Refrigeration Systems

– Standard 147, Reducing the Release of Halogenated Refrigerants

from Refrigerating and Air-Conditioning Equipment.

ASHRAE Position Document on Refrigerants and their Responsible Use

ASHRAE Standard 34

2L Flammability Classification

Standard 34

• Toxicity Classification Based on

– chronic (long term) measure

• Class A has PEL > 400 PPM

• Class B has PEL < 400 PPM

• PEL = Permissible Exposure Limit

• Flammability Classification Based on– ASTM E 681 with electrically activated match

– Class 1 - no flame propagation

– Class 2 - LFL > 0.10 kg/m^3

and hc < 19 MJ/kg

– Class 2L – Cl 2 w/ burning velocity < 10 cm / sec

– Class 3 - LFL < 0.10 kg/m^3

or hc > 19 MJ/kg

Standard 34 Activity

• ASHRAE 34 defined Class 2L

– Years of work to differentiate Class 2L from Class 2/3

– Single criteria: Flame speed < 10 cm/s

– Refrigerants that fall into new category include:

– Change in flammability rating does not alter toxicity

rating

– Approved by Standards Committee in Feb 2010

A2LA2L B2LB2L

R-32

R-143a

R-1234yf

R-1234ze

Ammonia

ISO 817:2005, Refrigerants – Designation System

• ISO 817:2005 is second edition of ISO 817

• First edition published in 1974

• Direct adoption of nomenclature system and

refrigerant designations included in Standard 34-

2004

• Does not include safety classifications

ISO/FDIS 817:2012, Refrigerants –

Designation and Safety Classification System

• Proposed third edition of ISO

817 includes safety

classification system in

Standard 34

• Standard under development

by ISO/TC 86/SC 8

• ASHRAE is secretariat of

committee

• Following countries are

participating members

(Countries in red participated

on working group developed

third edition of ISO/817 ):

• Belgium

• Bulgaria

• Denmark

• Egypt

• France

• Germany

• Italy

• Japan

• Republic of Korea

• Netherlands

• Poland

• Romania

• Russian Federation

• United Kingdom

• United States



• Final approval ballot, ISO/FDIS 817:2012, failed

with 9 positive and 6 negative votes

• 119 comments received

• SC 8 to meet April 18-19 to address comments

and prepare for second approval ballot

• Primary concerns expressed by members voting

against

– 1000 ppm default value for NOEL for cardiac

sensitization

– 2L flammability classification

– lack of requirements addressing toxicity of combustion

products.



• ISO 817 contains few variances from Standard 34

– More conservative refrigerant concentration limit (using

flammable concentration limit) for certain refrigerants,

set at 20% of the LFL vs. 25% of LFL in Standard 34

– Set CNS effect (anesthetic limit) as 100% of NOEL (no

observed effect level). Standard 34 sets limit as 80% of

NOEL

ASHRAE Standard 15

Standard 15

• First developed as Safety Code for Mechanical

Refrigeration in 1930

• Scope

– design, construction, installation, operation and

inspection of mechanical and absorption machines

– modifications if not identical in function and capacity

– refrigerant substitutions with different designation

• Generally written as self-sufficient document, it

normatively references other standards, including

Standard 34

Status

• Standard 15 Committee formed ad hoc committee

to draft requirements for use of all 2L refrigerants

based on data and additional information made

available to committee

• Prior to formal public review of proposed

changes, committee sought input through

Advisory Public Review

• Review of Addendum a to Standard 15-2010

initiated in July 2011

• Committee has reviewed comments and

continues to work on inclusion of requirements for

2L refrigerants

Class 2L Refrigerants Background

• Rules for Class 2L must be changed when

compared to Class 2 and 3 to be useful. Failing

this, there is no point in having Class 2L

• General guidance for Ad Hoc Working Group

– Understand safety considerations in real applications

considering most flammable refrigerants in new class

– Rules given in ISO 5149 for use of Class 2L should be

considered

– Standard 15 and IIAR 2 have rules for ammonia - rules

should not be altered

Correlations with Burning Velocity

1. Similar graphs for other properties (example : HOC)

2. Burning Velocity not a perfect measure but provides reasonable discrimination of refrigerants

Class 2L refrigerants are flammable and can be ignited

R-290 (39)

HFO-1234yf (5,000 - 10,000)

R-32 (30-100)

NH3 (100-300)

R-600a (45)

E-170 (54)

R-1150 (80)

Class 2L

R-152a

(Class 2)

Standard 15 Concept

• Avoid ignition event entirely

– Eliminate sources of ignition from areas where 2L

refrigerant migrates during leak event

• Provide air movement to mitigate ignition

– Risk of ignition directly proportional to time that large

refrigerant leak fills a space at concentration above

LFL. Use Ventilation to dilute and exhaust refrigerant

Standard 15 Committee needed technical justification

for proposed standards change through CFD and/or

testing.

Concepts Used for ASHRAE 15

• If RCL is exceeded, then equipment is located in

MER

– MER Emergency Ventilation is 30 ACH

• Lower edge of mechanical ventilation opening shall be as low

as practical (heavier than air refrigerant)

• Ceiling ventilation (lighter than air refrigerant = ammonia)

• Any permanent source of electrical ignition shall

be located > 0.5 m. above the ground, but not in

spill zone for any wall mounted unit.

• No open flames and hot surfaces (< 700 ̊C)

• Equipment located outdoors and low probability

system have no special requirements

• Consists of four parts

– Part 1 Definitions, classification and selection

criteria

– Part 2 Design, construction, testing, marking

and documentation

– Part 3 Installation site

– Part 4 Operation, maintenance, repair and

recovery

ISO/FDIS 5149 Refrigerating Systems and Heat Pumps –

Safety and Environmental Requirements

• Part 1 includes table of refrigerate charge

limitations, taking into consideration refrigerant

flammability classification

• Proposed class 2L limitations consider reduced

combustion risk as compared with class 2 and 3

refrigerants

• Standard would permit higher refrigerant

quantities of class 2L refrigerant than for class 2

or 3



• ASHRAE is secretariat of

committee

• Following countries are

participating members

(Countries in red

represented on working

group that developed

ISO/FDIS 5149):

– Australia

– Belgium

– Bulgaria

– Canada

– Denmark

– Egypt

– Finland

– France

– Germany

– India

– Italy

– Japan

– Republic of Korea

– Netherlands

– Poland

– Russian Federation

– United Kingdom

– United States





• Efforts began in 1997 to revise ISO 5149:1993,

Mechanical refrigerating systems used for cooling

and heating – Safety requirements, to include

environmental safety aspects and refrigeration

safety

• Based on EN 378

• Currently under development by ISO/TC 86/SC 1

ISO/FDIS 5149 Status

• ISP/5149-1 failed with 7 positive and 8 negative votes

(Parts 2 and 3 also failed; Part 4 passed). Total of 384

comments received on all parts

• Primary concerns expressed by members voting against

include:

– Drafting error in table for flammability class 3

– 2L refrigerant quantity limit requirements still being developed in

IEC, ASHRAE, UL JTG and AHRI working groups. Need for

harmonization before publication

– Treatment of class 3 refrigerant limits (alignment with EN 378, use

of either cap limits or absolute kg values)

• SC 1 met in January 2013 to resolve comments and

prepare for second approval ballot, expected to begin this

summer

Global Warming

2424

GWP

PowerGeneration

Summary

• ASHRAE and ISO Standards

– Including Low GWP Refrigerants

• A2L – Low burning velocity

• Natural Refrigerants

• Energy Efficiency is a Key

– CO2 Reduction Due to Power generation for HVAC&R

crh2013-WatsonTom (ASHRAE)

Documents

Transcript of crh2013-WatsonTom (ASHRAE)