B702-94

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1/16Copyright © 1998 American Water Works Association, All Rights Reserved.

American Water Works Association

ANSI/AWWA B702-94

(Revision of ANSI/AWWA B702-89)

AWWA STANDARD

FOR

SODIUM FLUOROSILICATE

Addendum B702a-97 is incorporated into this standard.

Effective date: Nov. 1, 1994.

First edition approved by AWWA Board of Directors May 27, 1954.

This edition approved Jan. 30, 1994.

Approved by American National Standards Institute Aug. 18, 1994.

AMERICAN WATER WORKS ASSOCIATION

6666 West Quincy Avenue, Denver, Colorado 80235

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AWWA Standard

This document is an American Water Works Association (AWWA) standard. It is not a specification.

AWWA standards describe minimum requirements and do not contain all of the engineering and

administrative information normally contained in specifications. The AWWA standards usually con-tain options that must be evaluated by the user of the standard. Until each optional feature is

specified by the user, the product or service is not fully defined. AWWA publication of a standard

does not constitute endorsement of any product or product type, nor does AWWA test, certify, or

approve any product. The use of AWWA standards is entirely voluntary. AWWA standards are

intended to represent a consensus of the water supply industry that the product described will

provide satisfactory service. When AWWA revises or withdraws this standard, an official notice of

action will be placed on the first page of the classified advertising section of Journal AWWA. The

action becomes effective on the first day of the month following the month of Journal AWWA publi-

cation of the official notice.

American National Standard

An American National Standard implies a consensus of those substantially concerned with its scope

and provisions. An American National Standard is intended as a guide to aid the manufacturer, the

consumer, and the general public. The existence of an American National Standard does not in any

respect preclude anyone, whether that person has approved the standard or not, from manufactur-

ing, marketing, purchasing, or using products, processes, or procedures not conforming to the stan-

dard. American National Standards are subject to periodic review, and users are cautioned to

obtain the latest editions. Producers of goods made in conformity with an American National Stan-dard are encouraged to state on their own responsibility in advertising and promotional materials

or on tags or labels that the goods are produced in conformity with particular American National

Standards.

C AUTION NOTICE: The American National Standards Institute (ANSI) approval date on the front

cover of this standard indicates completion of the ANSI approval process. This American National

Standard may be revised or withdrawn at any time. ANSI procedures require that action be taken

to reaffirm, revise, or withdraw this standard no later than five years from the date of publication.

Purchasers of American National Standards may receive current information on all standards by

calling or writing the American National Standards Institute, 11 W. 42nd St., New York, NY

10036; (212) 642-4900.

Copyright © 1994 by American Water Works Association

Printed in USA

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Committee Personnel

The AWWA Standards Committee on Fluorides, which reviewed and approved

this standard, had the following personnel at the time of approval:

Thomas G. Reeves, ChairJames A. McKinzey, Vice-Chair

Paul B. Maasen, Secretary

Consumer Members

Shahin Rezania, Minneapolis Water Works, Minneapolis, Minn. (AWWA)

Joseph Studgeon, Complex Administration — Bureau of Water,

Atlanta, Ga. (AWWA)

J.S. Trotter, City of Bloomington Utilities, Bloomington, Ind. (AWWA)

General Interest Members

Frederick Barker, Massachusetts Department of Public Health,

Boston, Mass. (NEWWA)

E.E. Baruth,* Standards Engineer Liaison, AWWA, Denver, Colo. (AWWA)

G.L. Hoffman,* Council Liaison, Finkbeiner, Pettis & Strout,

Akron, Ohio (AWWA)

R.M. Krill, Bureau of Water Supply, Madison, Wis. (AWWA)

M.L. Magnant, Department of Public Health, Des Moines, Iowa (AWWA)

T.G. Reeves, Centers for Disease Control, Atlanta, Ga. (AWWA)

D.H. Sanders,† Centers for Disease Control, Atlanta, Ga. (AWWA)

R.R. Smith, City of Atlanta Water Department, Austell, Ga. (AWWA)

J.U. Tamburini, Rothberg, Tamburini & Winsor Inc., Denver, Colo. (AWWA)

M.L. Wentink, Nebraska Department of Health, North Platte, Neb. (AWWA)

Producer Members

Chuck Krepshaw, Cargill Fertilizer Inc., Riverview, Fla. (AWWA)

M.E. Looney, Chemtech Products Inc., St. Louis, Mo. (AWWA)

P.B. Maasen, Kaiser Aluminum & Chemical Corporation,

Wentzville, Mo. (AWWA)

J.A. McKinzey, LCI Ltd., Ponte Vedra Beach, Fla. (AWWA)

*Liaison, nonvoting

†Alternate

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Foreword

I Introduction........................................ v

I.A Background ........................................ v

I.B History................................................ v

I.C Acceptance.......................................... v

II Special Issues.................................... vi

II.A Storage, Handling, and Safety

Precautions.......................................vi

III Use of This Standard ..................... vii

III.A Purchaser Options and Alternatives.................................. vii

III.B Modification to Standard ............... vii

IV Major Revisions .............................. vii

V Comments ...................................... viii

Standard

1 General

1.1 Scope................................................... 1

1.2 Purpose............................................... 1

1.3 Application ......................................... 1

2 References ....................................... 1

3 Definitions ....................................... 2

4 Requirements

4.1 Physical Requirements...................... 2

4.2 Chemical Requirements.................... 2

4.3 Impurities........................................... 2

5 Verification5.1 Sampling ............................................ 3

5.2 Test Procedures ................................. 4

6 Delivery

6.1 Marking.............................................. 6

6.2 Packaging and Shipping ................... 7

6.3 Affidavit of Compliance or

Certified Analyses........................... 7

Contents

All AWWA standards follow the general format indicated subsequently. Some variations from this format maybe found in a particular standard.

SEC. PAGE SEC. PAGE

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Foreword

This foreword is for information only and is not a part of AWWA B702.

I. Introduction

I.A. Background. Sodium fluorosilicate (Na2SiF6) is one of several compoundspresently being added to drinking water to reduce the incidence of dental caries.

Since the first fluoridation installations during 1945, studies have shown that dental

decay can be reduced by 20 to 40 percent among children who have consumed fluori-

dated water since birth.

Sodium fluorosilicate is a white or yellowish-white, slightly hydroscopic, crys-

talline powder with limited solubility in water. Although odorless, it has an acid

taste. Sodium fluorosilicate has no true melting point, and decomposition begins at

about 500°C (932°F) with the formation of silicon tetrafluoride. Its molecular weight

is 118.1 and its specific gravity is 1.36. At 0°C (32°F), solubility is 0.43 g/100 mL

water, and increases to 2.45 g/100 mL water at 100°C (212°F). It hydrolyzes in

water to form a solution, with a pH between 3.5 and 4.0. Sodium fluorosilicate is

manufactured principally from fluorosilicic acid.

Sodium fluorosilicate is fed into the water by means of mechanical feeders

designed for this purpose. The feeders are equipped with solution tanks, which

should completely dissolve the compound before its introduction into the water. Liq-

uid proportioning of solutions is rarely used because of the difficulty in making

constant-strength solutions. Feeding of slurries (solutions containing undissolved

particles) is not recommended because of the resulting variations in fluoride levels.

Refer to AWWA Manual M4, Water Fluoridation Principles and Practices,* for

additional technical information concerning the application and use of sodium

fluorosilicate.

I.B. History. This standard was first published in the August 1954 issue of

Journal AWWA as tentative, having been approved on May 27, 1954, by the AWWA

Board of Directors. The second, third, fourth, and fifth editions were approved on

May 15, 1960; Jan. 24, 1971; Jan. 30, 1984; and Jan. 29, 1989, respectively. Thisedition was prepared by the AWWA Standards Committee on Fluorides.

I.C. Acceptance. In May 1985, the US Environmental Protection Agency

(USEPA) entered into a cooperative agreement with a consortium led by NSF Inter-

national (NSF) to develop voluntary third-party consensus standards and a certifica-

tion program for all direct and indirect drinking water additives. Other members of

the original consortium included the American Water Works Association Research

Foundation (AWWARF) and the Conference of State Health and Environmental

Managers (COSHEM). The American Water Works Association (AWWA) and the

Association of State Drinking Water Administrators (ASDWA) joined later.

In the United States, authority to regulate products for use in, or in contact

with, drinking water rests with individual states.† Local agencies may choose to

v

*Water Fluoridation Principles and Practices, AWWA Manual M4, AWWA, Denver, Colo.(1988).

†Persons in Canada, Mexico, and non-North American countries should contact theappropriate authority having jurisdiction.

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impose requirements more stringent than those required by the state. To evaluate

the health effects of products and drinking water additives from such products, state

and local agencies may use various references, including two standards developed

under the direction of NSF, ANSI*/NSF† 60, Drinking Water Treatment Chemicals

—Health Effects, and ANSI/NSF 61, Drinking Water System Components—Health

Effects.

Various certification organizations may be involved in certifying products inaccordance with ANSI/NSF 60 (61). Individual states or local agencies have author-

ity to accept or accredit certification organizations within their jurisdiction. Accredi-

tation of certification organizations may vary from jurisdiction to jurisdiction.

Appendix A, “Toxicology Review and Evaluation Procedures,” to ANSI/NSF 60

(61) does not stipulate a maximum allowable level (MAL) of a contaminant for

substances not regulated by a USEPA final maximum contaminant level (MCL). The

MALs of an unspecified list of “unregulated contaminants” are based on toxicity

testing guidelines (noncarcinogens) and risk characterization methodology (carcino-

gens). Use of Appendix A procedures may not always be identical, depending on the

certifier.

AWWA B702-94 addresses additives requirements in Sec. 4.3 of the standard.

The transfer of contaminants from chemicals to processed water or the residual sol-ids is becoming a problem of greater concern. The language in Sec. 4.3.5 is a recom-

mendation only for direct additives used in the treatment of potable water to be

certified by an accredited certification organization in accordance with ANSI/NSF

Standard 60, Drinking Water Treatment Chemicals—Health Effects. However, users

of the standard may opt to make this certification a requirement for the product.

Users of this standard should also consult the appropriate state or local agency

having jurisdiction in order to

1. Determine additives requirements, including applicable standards.

2. Determine the status of certifications by all parties offering to certify prod-

ucts for contact with, or treatment of, drinking water.

3. Determine current information on product certification.

II. Special Issues.

II.A. Storage, Handling, and Safety Precautions. Sodium fluorosilicate must be

stored in a clean, dry location. The storage area must be well ventilated. Sodium

fluorosilicate has a tendency to compact or cake when exposed to moisture, when

bags are stacked too high, or during long periods of storage. Bags of sodium

fluorosilicate should be stored on pallets in stacks not more than six bags high to

minimize compaction.

Sodium fluorosilicate is hazardous if swallowed or inhaled in large amounts.

Ingestion of 4 to 5 g of fluoride ion (F–) per 150 lb (69 kg) body weight may be fatal.

The inhalation of sodium fluorosilicate dust should be avoided. Protective safety

gear should be worn when handling sodium fluorosilicate. The following list of pro-

tective clothing and equipment should be the minimum available:

1. A high-efficiency dust respirator (chemical mask) with a soft rubber face-

to-mask seal and replaceable cartridges approved by the National Institute for Occu-pational Safety and Health/Mine Safety Health Administration (NIOSH/MSHA).‡

vi

*American National Standards Institute, 11 W. 42nd St., New York, NY 10036.

†NSF International, 3475 Plymouth Rd., Ann Arbor, MI 48106.

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2. Gauntlet neoprene gloves (12-in. [304-mm] minimum glove length).

3. Heavy-duty neoprene aprons.

Feeders should be equipped with dust collectors. Spills should be cleaned up

immediately. Personnel should wash thoroughly after handling sodium fluorosilicate.

For additional safety aspects, refer to material safety data sheets (MSDS) available

from the chemical supplier or manufacturer.

III. Use of This Standard. It is the responsibility of the user of an AWWA standard to determine that the products described in that standard are suitable for

use in the particular application being considered.

III.A. Purchaser Options and Alternatives. The following items should be cov-

ered in the purchaser’s specifications:

1. Standard used — that is, AWWA B702, Standard for Sodium Fluorosili-

cate, of latest revision.

2. If an affidavit of compliance, a certified analysis, or both, are required

(Sec. 6.3).

3. Quantity required.

4. Additional size requirements for feedability and dust suppression if desired

(see paragraphs below and Sec. 4.1).

5. Form of shipment — bulk, package, size (weight), and type of package(Sec. 6.2).

6. Whether the recommended compliance with ANSI/NSF Standard 60,

Drinking Water Treatment Chemicals—Health Effects, is to be required. If this cer-

tification is to be required, the purchaser’s specifications shall read, “This material

shall be certified as suitable for contact with or treatment of drinking water by an

accredited certification organization in accordance with ANSI/NSF Standard 60,

Drinking Water Treatment Chemicals—Health Effects.”

The specific requirements for a material that is of proper screen size for the

feeding equipment being used and that will remain “free flowing” after a definite

period and condition of storage are matters that should be agreed on by both pur-

chaser and supplier before shipment. At this time, widely varying methods of feed-

ing and storing sodium fluorosilicate preclude the possibility of including a firm

standard on size to satisfy all these variables. Feedability appears to depend on the

uniformity of size between US Standard Sieves No. 100 (150 µm) and No. 325

(44 µm) (a narrow size distribution) and a low-moisture content.

For the suppression of dust, materials containing the least amount of particles

finer than 325 mesh are preferred.

III.B. Modification to Standard. Any modification of the provisions, definitions,

or terminology in this standard must be provided in the purchaser’s specifications.

IV. Major Revisions. Major changes made in this revision of the standard

include the following:

1. The format has been changed to the current AWWA style for standards.

2. The acceptance clause (Sec. I.C) and the definitions of parties (Sec. 3) have

been revised to approved wording.

vii

‡NIOSH/MSHA approval is given to various masks. Each brand is evaluated byNIOSH/MSHA for the proposed use and conditions. Available from the National Institute forOccupational Safety and Health, 4676 Columbia Parkway, Cincinnati, OH 45226; or MineSafety and Health Administration, 4015 Wilson Boulevard, Arlington, VA 22203.

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3. Editorial revisions have been included throughout the standard.

4. The name of the compound that is the subject of the standard has been

changed from sodium silicofluoride to sodium fluorosilicate, which is the internation-

ally recognized name.

V. Comments. If you have any comments or questions about this standard,

please call the AWWA Standards Department, (303) 794-7711 ext. 2201, FAX (303)

795-1440, or write to the department at 6666 W. Quincy Ave., Denver, CO 80235.

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American Water Works Association

ANSI/AWWA B702-94

(Revision of ANSI/AWWA B702-89)

AWWA STANDARD FOR

SODIUM FLUOROSILICATE

SECTION 1: GENERAL

Sec. 1.1 Scope

This standard covers sodium fluorosilicate (Na2SiF6) for water supply service

application.

Sec. 1.2 Purpose

The main purpose of this standard is to provide purchasers, manufacturers,

and suppliers with the minimum requirements for sodium fluorosilicate, including

physical, chemical, packaging, shipping, and testing requirements.

Sec. 1.3 ApplicationThis standard can be referenced in specifications for purchasing and receiving

sodium fluorosilicate and can be used as a guide for testing the physical and chemi-

cal properties of sodium fluorosilicate samples. The stipulations for this standard

apply when this document has been referenced and only to sodium fluorosilicate

used in water supply service application.

SECTION 2: REFERENCES

This standard references the following document. In its latest edition, it forms

a part of this standard to the extent specified in this standard. In any case of con-

flict, the requirements of this standard shall prevail.

Standard Methods for the Examination of Water and Wastewater. APHA,*

AWWA, and WEF.† Washington, D.C. (18th ed., 1992).

1

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*American Public Health Association, 1015 15th St. N.W., Washington, DC 20005.

†Water Environment Federation, 601 Wythe St., Alexandria, VA 22314-1994.

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SECTION 3: DEFINITIONS

The following definitions shall apply to this standard:

1. Manufacturer: The party that manufactures, fabricates, or produces mate-

rials or products.

2. Purchaser: The person, company, or organization that purchases anymaterials or work to be performed.

3. Supplier: The party that supplies materials or services. A supplier may

or may not be the manufacturer.

SECTION 4: REQUIREMENTS

Sec. 4.1 Physical Requirements*

4.1.1 Size and density. The sodium fluorosilicate supplied under this standard

shall be a fine, dry, granular material containing no lumps and shall have an aver-

age bulk density of approximately 85 lb/ft3 (1.4 g/cm

3) (range from 85–95 lb/ft

3

[1.4–1.6 g/cm3]). The material shall meet the following size requirements:

1. At least 98 percent shall pass through a US Standard Sieve No. 40

(420 µm).

2. Less than 25 percent shall pass through a US Standard Sieve No. 325

(44 µm).

4.1.2 Anticaking agents. Anticaking agents may be used if they do not produce

any interference with normal water treatment processes, such as coagulation and

sedimentation, and do not impart any taste, odor, or toxicity to water when it is

treated with the normal quantity of sodium fluorosilicate.

Sec. 4.2 Chemical Requirements

The chemical composition shall be determined by the test methods specified in

Sec. 5.2.

4.2.1 Sodium fluorosilicate content. The sodium fluorosilicate supplied under

this standard shall have a minimum of 98 percent (dry basis) sodium fluorosilicate,

which corresponds to approximately 59.4 percent fluoride ions.

4.2.2 Moisture. Moisture content shall not exceed 0.5 percent by weight.

Sec. 4.3 Impurities†

4.3.1 General impurities. The sodium fluorosilicate supplied under this stand-

ard shall contain no soluble materials or organic substances in quantities capable of

producing deleterious or injurious effects on the health of those consuming a water

that has been treated properly with the sodium fluorosilicate.

2 AWWA B702-94

*All sieve numbers referred to in this standard are US Standard Sieve Series numbers, asspecified in the American Society for Testing and Materials (ASTM) Standard DesignationE11, Specification for Wire-Cloth Sieves for Testing Purposes. Available from ASTM, 1916Race St., Philadelphia, PA 19103.

†See Sec. I.C of the foreword.

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4.3.2 Insoluble matter. Insoluble matter shall not exceed 0.5 percent by

weight.

4.3.3 Heavy metals. Heavy metals, expressed as lead (Pb), shall not exceed

0.05 percent by weight.

4.3.4 Additional impurity limits. Additional impurity limits may be specified

by the purchaser to ensure that the material supplied is suitable for water treat-

ment. If additional impurity limits are specified by the purchaser, then thepurchaser must state the testing methods to be used to determine compliance with

the additional limits.

4.3.5 Product certifications. Sodium fluorosilicate is a direct additive used in

the treatment of potable water. This material should be certified as suitable for

contact with or treatment of drinking water by an accredited certification organiza-

tion in accordance with ANSI/NSF Standard 60, Drinking Water Treatment

Chemicals—Health Effects. Evaluation shall be accomplished in accordance with re-

quirements that are no less restrictive than those listed in ANSI/NSF Standard 60.

Certification shall be accomplished by a certification organization accredited by the

American National Standards Institute.

SECTION 5: VERIFICATION

Sec. 5.1 Sampling

Sampling shall be conducted in accordance with this section of the standard.

Each sample container shall be labeled to identify it and shall be signed by the

sampler. A chain-of-custody form shall accompany all samples and shall be properly

completed by the individuals collecting samples.

5.1.1 Sampling point. Samples shall be taken at the point of destination.

5.1.2 Sampling device. Sodium fluorosilicate may be sampled by means of a

sampling tube that is at least 3 ⁄ 4 in. (19 mm) in diameter. If the sodium fluorosili-

cate is handled by conveyor or elevator, a mechanical sampling arrangement may beused. The arrangement must provide a representative sampling of the entire ship-

ment that is being handled.

5.1.3 Amount of shipment to be sampled. If the sodium fluorosilicate is pack-

aged, 5 percent of the packages shall be sampled. No sample for testing shall be

taken from a broken package. Samples from individual packages shall be combined

to form a composite sample.

5.1.4 Sample size and handling. The composite sample, weighing at least

16 lb (7.3 kg), shall be mixed thoroughly and divided in the following manner:

1. Divide into four 4-lb (1.8-kg) sections.

2. Select alternate quarters.

3. Redivide each to provide eight 1-lb (0.5-kg) sections.

4. Select six 1-lb (0.5-kg) samples.

5.1.5 Sample storage. The 1-lb (0.5-kg) samples shall be sealed in airtight,

moistureproof, plastic or glass containers each carefully identified by a label signed

by the sampler. Two samples are to be used by the purchaser for the tests specified

in Sec. 5.2. The other four shall be retained for at least 30 days after the date of

receipt, to be used for retesting as provided in Sec. 5.2.7.

SODIUM FLUOROSILICATE 3

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Sec. 5.2 Test Procedures

Testing of sodium fluorosilicate shall be conducted in accordance with the pro-

cedures presented in this standard. Alternate procedures can be used only with

written approval from the purchaser. In any case of conflict, the test procedures of

this standard shall prevail.

5.2.1 Test samples. Test samples shall be obtained from the 1-lb (0.5-kg) sam-

ples taken in accordance with Sec. 5.1. Samples shall be stored in an airtight

container and unsealed only when it is necessary to remove quantities of material

for testing. Removal of material shall be accomplished as rapidly as possible to avoid

changes in moisture content, and the sample container shall then be resealed for

future reference.

5.2.2 Test procedure for size. Rapidly weigh approximately 100 g of sample to

the nearest 0.1 g and screen until constant weight is achieved on the appropriate US

Standard Sieve Series to determine compliance with the size requirements of Sec.

4.1. Weigh to the nearest 0.1 g the amounts of material passing through the sieve or

being retained on the sieve. Report each portion of material passing through the

sieve or retained on the sieve as a percent of the total initial sample. The entire

process should be accomplished in a dry atmosphere and as quickly as possible.

5.2.3 Test procedure for insoluble matter.5.2.3.1 Procedure.

1. Weigh 2 g of the sample that has been previously dried at 105°C to con-

stant weight and transfer into a beaker. Dissolve in 500 mL of hot deionized water.

Generally 15 to 30 min is sufficient time for dissolution.

2. Filter through a tared Gooch crucible or a tared fritted-glass filter of

medium porosity. Wash with at least six separate 25-mL portions of boiling deion-

ized water, allowing the crucible to drain between washings. Dry the crucible or

filter at 105°C to constant weight.

5.2.3.2 Calculation.

weight of residue

weight of sample

× 100 = percent insoluble matter (Eq 1)

5.2.4 Test procedure for moisture content.

5.2.4.1 Procedure.

1. Weigh 5 g of the sample into a previously dried and cooled broad weighing

bottle and heat in an oven at 105°C to constant weight. Cool in a desiccator and

reweigh.

5.2.4.2 Calculate the percent of moisture.

loss in weight

weight of sample × 100 = percent of moisture (Eq 2)

5.2.5 Test procedure for sodium fluorosilicate and fluoride content.

5.2.5.1 Reagents. 1. Alcoholic potassium chloride solution — dissolve 60 g of potassium chloride

in 400 mL of recently boiled-and-cooled deionized water and add 400 mL of 95 per-

cent neutral ethyl alcohol.

2. Alcoholic potassium chloride and sodium carbonate solution — dissolve 1 g

of sodium carbonate in 100 mL of alcoholic potassium chloride solution from step 1.

3. Standard sodium hydroxide solution, 0.2 N .

4 AWWA B702-94

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4. Phenolphthalein indicator, 1 percent.

5.2.5.2 Procedure.

1. Weigh 0.4 g of sample that has been dried at 105°C to constant weight and

transfer into a beaker. While stirring continuously, rapidly add 25 mL of alcoholic

potassium chloride/sodium carbonate solution. Add more if necessary, until solution

pH is greater than 7. The solution must not be acidic.

2. Filter with a Buchner funnel or filter crucible with suction and wash theprecipitate with alcoholic potassium chloride solution until the wash liquid is not

alkaline to phenolphthalein.

3. Transfer the filter paper and contents to a beaker and add 100 mL of

recently boiled deionized water and 1 to 2 mL of phenolphthalein indicator. Heat to

70–90°C and titrate with 0.2 N sodium hydroxide to first pink color. Continue heat-

ing and complete the titration with the solution actively boiling.

5.2.5.3 Calculation.*

mL NaOH × N × 0.047

weight of sample, in grams × 100 = percent Na2SiF6 (Eq 3)

percent Na2SiF

6 × 0.606 = percent F

5.2.6 Test procedure for heavy metals.

5.2.6.1 Reagents

1. Concentrated hydrochloric acid.

2. Ammonium hydroxide, 10 percent.†

3. 0.1 N hydrochloric acid.

4. Hydrogen sulfide, saturated solution.‡

5. Lead nitrate, American Chemical Society (ACS)§ reagent grade.

6. Concentrated nitric acid.

7. Lead nitrate stock solution. Dissolve 400.0 mg of ACS-reagent-grade lead

nitrate [Pb(NO3)2] in 100 mL of deionized water containing 1 mL of concentrated

nitric acid. Dilute to 1000.0 mL with deionized water. Prepare and store this solu-

tion in glass containers that are free from lead salts. 8. Standard lead solution. On the day of use, dilute 10.0 mL of the lead

nitrate stock solution to 100.0 mL with deionized water (20 mL of this solution

contains 0.50 mg of lead, which is equivalent to 1.0 mg [0.05 percent] of heavy

metals calculated as lead in 2.0 g of sodium fluorosilicate).

5.2.6.2 Procedure.

*Based on the following equations:

Na2SiF6 + 2KCl → K 2SiF6 + 2NaCl

K 2SiF6 + 4NaOH → 2KF + 4NaF + SiO2 + 2H2O

†C AUTION: Ammonium hydroxide fumes can cause damage to eyes and lungs. Use in awell-ventilated area or under a fume hood.

‡C AUTION: Hydrogen sulfide is an extremely poisonous gas. Avoid breathing fumes. Use ina well-ventilated area or under a fume hood.

§American Chemical Society, 1155 16th St. N.W., Washington, DC 20036.


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1. In a platinum dish, treat 2.0 g of sample that has been previously dried at

105°C to constant weight with 10 mL of concentrated hydrochloric acid and evapo-

rate to dryness under a fume hood. Repeat with another 10 mL of concentrated

hydrochloric acid.

2. Dissolve the residue in 40 mL of deionized water.

3. Measure out 20 mL of this solution into a 100-mL beaker and adjust to

pH 3–4 with 10 percent ammonium hydroxide† or 0.1 N hydrochloric acid or both. 4. Add 10 mL of a freshly prepared, saturated solution of hydrogen sulfide‡ in

deionized water.

5. The brown color produced should not be greater than that formed in 20 mL

of the standard lead solution after treatment as in steps 3 and 4.

5.2.7 Rejection.

5.2.7.1 Notice of nonconformance. If the sodium fluorosilicate delivered does

not meet the requirements of this standard, a notice of nonconformance shall be

provided by the purchaser to the supplier within 10 working days after receipt of the

shipment at the point of destination. The results of the purchaser’s tests shall pre-

vail, unless the supplier notifies the purchaser within five working days after receipt

of the notice of nonconformance that a retest is desired. On receipt of the request for

a retest, the purchaser shall forward to the supplier one of the sealed samples takenin accordance with Sec. 5.1 of this standard. In the event that the results obtained

by the supplier on retesting do not agree with the results obtained by the purchaser,

the other sealed sample shall be forwarded, unopened, for an analysis to a referee

laboratory agreed on by both parties. The results of the referee analysis shall be

accepted as final. The cost of the referee analysis shall be paid by the supplier if the

material does not meet the requirements of this standard, or by the purchaser if the

material does meet the requirements of this standard.

5.2.7.2 Material originating outside of North America. On request of the pur-

chaser, the supplier shall inform the purchaser of the origin of the sodium

fluorosilicate to be furnished. If the material to be furnished was manufactured out-

side of North America, the purchaser may request from the supplier a written

statement presenting the steps the supplier will take to ensure that the material to

be supplied conforms to the requirements of this standard.

5.2.7.3 Torn bags. Ripped or torn bags are not acceptable.

SECTION 6: DELIVERY*

Sec. 6.1 Marking

6.1.1 Required. Each package and container shall have legibly marked on it

the name of the compound, the net weight of the contents, the name of the manufac-

turer, the lot number, and the brand name (if any). Each package shall bear such

other markings as are required by the US Department of Transportation (USDOT)

and other applicable laws. When shipped in bulk, this information shall accompany

the bill of lading.

6 AWWA B702-94

*Governmental marking, packaging, and shipping references reflect US requirements.Users of AWWA B702 in Canada, Mexico, and non-North American countries should verifyapplicable local and national regulatory requirements.

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6.1.2 Optional. Packages may also bear the statement, “This material meets

the requirements of AWWA B702-94, Standard for Sodium Fluorosilicate,” provided

that the requirements of this standard are met and the material is not of a different

quality in separate agreement between the supplier and purchaser.

Sec. 6.2 Packaging and Shipping *

6.2.1 Packaging. Bags, drums, and any other nonbulk container used for pack-aging sodium fluorosilicate shall comply with all applicable paragraphs of HM-181,

part 178 (specifications for packaging) of CFR 49.†

6.2.2 Shipping regulations. Packaging and shipping of sodium fluorosilicate

shall conform to all applicable local, state, and federal regulations.

6.2.3 Containers. Sodium fluorosilicate may be shipped in multiwall paper

bags, fiber drums, supersacks, bulk, or other USDOT-approved containers as speci-

fied by the purchaser. Where feasible, all bags should be constructed with vapor

barrier liners. (Generally, multiwalled bags come in 100-lb [45-kg] or 50-lb [22.5-kg]

sizes.)

6.2.4 Net weight. The net weight of packages shall not deviate from the

recorded weight by more than ± 2.5 percent. If exception is taken to the weight of

the material received, it shall be based on a certified unit weight of not less than10 percent of the packages shipped, selected at random from the entire shipment.

Sec. 6.3 Affidavit of Compliance or Certified Analyses

The purchaser may require either (1) an affidavit from the manufacturer or

supplier that the sodium fluorosilicate furnished under the purchaser’s specifications

complies with all applicable requirements of this standard; or (2) certified analyses

of the sodium fluorosilicate, furnished by the manufacturer or supplier, covering

such items as required; or (3) both.


*Because of frequent changes in these regulations, all parties should remain informed of possible revisions. Provisions of the purchaser’s specifications should not preclude compliancewith applicable regulations.

†Code of Federal Regulations, Title 49, part 178 (Transportation). Superintendent of Documents, US Government Printing Office, Washington, DC 20402.

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3P-3C-42702-7/98-RM Printed on recycled paper.

B702-94

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Transcript of B702-94