sub-committee on ship systems and equipment original

I:\SSE\07\SSE 7-INF.4.docx

E

SUB-COMMITTEE ON SHIP SYSTEMS AND EQUIPMENT 7th session Agenda item 7

SSE 7/INF.4

6 January 2020 Original: ENGLISH ONLY

Pre-session public release: ☒

AMENDMENTS TO GUIDELINES FOR THE APPROVAL OF FIXED DRY CHEMICAL

POWDER FIRE-EXTINGUISHING SYSTEMS FOR THE PROTECTION OF SHIP CARRYING LIQUEFIED GASES IN BULK (MSC.1/CIRC.1315)

Information and interim report evaluating dry chemical powder agents according to

standard ISO 7202 criteria

Submitted by the United States

SUMMARY

Executive summary: This document provides information and a preliminary technical report on dry chemical powder agents, properties and the suitability of standard ISO 7202 testing

Strategic direction,

if applicable:

Other work

Output: OW 39

Action to be taken: 8

Related documents: MSC 98/23; SSE 5/9, SEE 5/17; SSE 6/7, SSE 6/18; SSE 7/7 and SSE 7/7/1

General 1 At its ninety-eighth session, the Maritime Safety Committee (MSC) tasked the Sub-Committee to review and amend the Guidelines for the approval of fixed dry chemical powder fire-extinguishing systems for the protection of ships carrying liquefied gases in bulk (MSC.1/Circ.1315). 2 The amendments to MSC.1/Circ.1315 focused on developing new test methods or incorporating an existing performance-based standard, such as standard ISO 7202. The United States notes that some Administrations may be unfamiliar with the consensus standard ISO 7202 or may question how the standard differentiates between suitable or unsuitable fire-extinguishing agents for class B fires.

SSE 7/INF.4

I:\SSE\07\SSE 7-INF.4.docx

3 The test methods and criteria in standard ISO 7202 include fire test procedures, as well as material testing of dry powder agents to determine their properties, including fluidity and susceptibility to caking and clogging. 4 The United States sponsored research on the standard ISO 7202 test methods and acceptability criteria to assess the suitability of standard ISO 7202 for incorporation into MSC.1/Circ.1315. This research addresses concerns related to clogging, caking, clumping and fire performance of different fire suppression agents. The agents tested in this research include sodium bicarbonate, potassium bicarbonate and agents based on neither sodium nor potassium. 5 The United States developed an interim report based on the results gathered to date, as set out in the annex. The research project is not complete, however, a final report will be published prior to this session. 6 Fire testing and additional material property testing of potassium, sodium, potassium/sodium mixtures and dry powders which don't include sodium or potassium agents, including commercially available products will be done and included in the final report. 7 Once the full testing program is complete, the final report may be obtained in portable data format (PDF) from the U.S. Coast Guard Office of Design and Engineering Standards, Lifesaving and Fire Protection Division (CG-ENG-4) web page using the following URL: https://www.dco.uscg.mil/CG-ENG-4/Research/ Action requested of the Sub-Committee 8 The Sub-Committee is invited to note the results of the testing when considering document SSE 7/7/1, as set out in the annex, and to consider the findings in the development of updates to the MSC.1/Circ.1315.

***

https://www.dco.uscg.mil/CG-ENG-4/Research/

SOUTHWEST RESEARCH INSTITUTE6220 CULEBRA ROAD 78238-5166 • P.O DRAWER 28510 78228-0510 • SAN ANTONIO, TEXAS, USA • (2101 684-5111 • WWW SWRI ORG

CHEMISTRY AND CHEMICAL ENGINEERING DIVISION FIRE TECHNOLOGY DEPARTMENTWWW.FIRE.SWRI.ORG

FAX (210) 522-3377

0

EVALUATION OF SODIUM AND POTASSIUMCHEMICAL FIRE EXTINGUISHING STANDARDS

TASK 4: INTERIM REPORTConsisting of 37 Pages

USCG ORDER No.: 70Z02319PMSE08600SwRI® Project No.: 01.24804.01.001Test Dates: September 26 — November 26, 2019Report Date: December 10, 2019

Prepared for:

United States Coast Guard2703 Martin Luther King Jr Ave SEWashington, DC 20593

Submitted by:

Jason P. HuczekPrincipal EngineerEngineering and Research Section

This report is for the information of the client. It may be used in its entirety for the purpose of securing product acceptance from dulyconstituted approval authorities. This report shall not be reproduced except in full, without the written approval of SwRI. Neither this

report nor the name of the lnntitute shall be used in publicity or advertiaing.

Benefiting government, industry and the public through innovalive science and technology

Approved by:

DirectorFire Technology Department

ANNEX SSE 7/INF.4

United States Coast Guard 2 SwRI Project No.: 01.24804.01.001

TABLE OF CONTENTS

PAGE

1.0 BACKGROUND ................................................................................................................... 5

2.0 TEST SPECIMENS ................................................................................................................ 6

3.0 TEST PROCEDURES ............................................................................................................ 8

3.1 ISO 7202 ........................................................................................................................ 8

3.1.1 Section 13.4 – Fluidity Test ................................................................................... 9

3.1.2 Section 13.5 – Test for Resistance to Caking and Clumping ................................ 9

3.1.3 Section 13.6 – Water Repellence Test ................................................................. 10

3.1.4 Section 13.7 – Test Method for Moisture Content .............................................. 10

3.1.5 Section 13.9 – Moisture Absorption Testing ....................................................... 11

3.2 UL 299 ......................................................................................................................... 11

3.2.1 Section 48.2 – Elevated Temperature Test .......................................................... 11

3.2.2 Section 48.3 – Hygroscopicity Test ..................................................................... 12

3.3 ISO 11358-1 – TGA Testing ....................................................................................... 12

4.0 TEST RESULTS ................................................................................................................. 13

4.1 ISO 7202 – Section 13.4 – Fluidity Test ..................................................................... 13

4.2 ISO 7202 – Section 13.5 – Test for Resistance to Caking and Clumping ................... 15

4.3 ISO 7202 – Section 13.6 – Water Repellence Test ..................................................... 18

4.4 ISO 7202 – Section 13.7 – Test Method for Moisture Content ................................... 18

4.5 ISO 7202 – Section 13.9 – Moisture Absorption Testing ........................................... 20

4.6 UL 299 – Section 48.2 – Elevated Temperature Test .................................................. 22

4.7 UL 299 – Section 48.3 – Hygroscopicity Test ............................................................ 26

4.8 ISO 11358-1 (TGA Testing) ....................................................................................... 30

5.0 DATA ANALYSIS .............................................................................................................. 32

6.0 NEXT STEPS ..................................................................................................................... 37


LIST OF FIGURES

PAGE Figure 1. Left: NaHCO3 Base, Center: KHCO3 Base, Right: Additives. ...................................... 7

Figure 2. Left: Stand Mixer, Center: Flour/Grain Mill, Right: Sieve Shaker. .............................. 7

Figure 3. Left: Thermal Cycling Chamber, Right: Salt/Fog Test Apparatus. ............................... 8

Figure 4. Left: Schematic of Fluidity Test Device, Right: Photograph of SwRI’s Fluidity

Device. ....................................................................................................................................... 9

Figure 5. Left: Desiccator with Salt Solution, Right: Oven used for Temperature Exposure. ... 10

Figure 6. Left: Samples that completely absorbed Water Droplets, Right: Samples that did not

completely absorb the Water Droplets. ................................................................................... 10

Figure 7. Left: Samples in Tin Cans, Right: Oven for Elevated Temperature Test. ................... 11

Figure 8. Left: Conditioning Chamber (1 of 2), Right: Conditioning Salts. ............................... 12

Figure 9. SwRI’s TGA/DSC Test Apparatus. ............................................................................. 13

Figure 10. Left: Schematic of Fluidity Test Device, Right: Photograph of SwRI’s Fluidity

Device. ..................................................................................................................................... 14

Figure 11. Photograph Array of Final Results for Testing per ISO 7202, Section 13.5. .............. 17

Figure 12. Graphical Results of ISO 7202, Section 13.7 Testing. ................................................ 20

Figure 13. Graphical Results of ISO 7202, Section 13.7 Testing (Zoomed in on Y-Axis). ......... 20

Figure 14. Graphical Results of ISO 7202, Section 13.9 Testing. ................................................ 22

Figure 15. Photograph Array of Final Results for Testing per UL 299, Section 48.2. ................. 25

Figure 16. Photograph Array of Final Results for Testing per UL 299, Section 48.3. ................. 29

Figure 17. TGA/DSC Test Results for K1a at 5 K/min Ramp Rate. ............................................ 30

Figure 18. TGA/DSC Test Results for Na1a at 5 K/min Ramp Rate. .......................................... 31

Figure 19. TGA/DSC Test Results for Na3a at 5 K/min Ramp Rate. .......................................... 31

Figure 20. Summary of Stacked Total Rank Scores for All Samples. .......................................... 35

Figure 21. Summary of Stacked Total Rank Scores for Non-Weathered Specimens. .................. 35

Figure 22. Summary of Stacked Total Rank Scores for Weathered Specimens. .......................... 36

Figure 23. Summary of Rank Scores Organized by Test Variable. .............................................. 37


LIST OF TABLES PAGE

Table 1. Phase 1 Test Sample Matrix. ................................................................................................ 6

Table 2. Phase 1 Test Results – ISO 7202 Section 13.4. .................................................................. 14

Table 3. Phase 1 Test Results – ISO 7202 Section 13.5 (Sodium-Based Samples). ......................... 15

Table 4. Phase 1 Test Results – ISO 7202 Section 13.5 (Potassium-Based Samples). ..................... 16

Table 5. Phase 1 Test Results – ISO 7202 Section 13.6 (Water Repellence). .................................. 18

Table 6. Phase 1 Test Results – ISO 7202 Section 13.7 (Moisture Content). ................................... 19

Table 7. Phase 1 Test Results – ISO 7202 Section 13.9 (Moisture Absorption)............................... 21

Table 8. Phase 1 Test Results – UL 299 Section 48.2 (Sodium-Based Samples). ............................ 23

Table 9. Phase 1 Test Results – UL 299 Section 48.2 (Potassium-Based Samples). ........................ 24

Table 10. Phase 1 Test Results – UL 299 Section 48.3 (Sodium-Based Samples). .......................... 27

Table 11. Phase 1 Test Results – UL 299 Section 48.3 (Potassium-Based Samples). ...................... 28

Table 12. Phase 1 Test Results – Summary of Pass/Fail Results for ISO 7202. ............................... 33

Table 13. Phase 1 Test Results – Summary of Pass/Fail Results for UL 299. .................................. 33

Table 14. Phase 1 Test Results – Summary of Test Result Rankings – ISO 7202............................ 34

Table 15. Phase 1 Test Results – Summary of Test Result Rankings – UL 299. .............................. 34

Table 16. Phase 1 Test Results – Summary of Ranking Results by Test Variable. .......................... 36


1.0 BACKGROUND

The Commercial Regulations & Standards Directorate (CG-5PS) of the United States Coast

Guard (USCG) is responsible for the approval of fire protection equipment carried on U.S. flagged

vessels and for the development and maintenance of the standards and regulations that form the basis

for those approvals. As part of that process, the USCG aids in the development of standards at the

International Maritime Organization (IMO) in the Marine Safety Committee (MSC) and Ship Systems

and Equipment (SSE) Subcommittee. IMO members have proposed to ban sodium-based agents used

in dry chemical fire extinguishing systems that are used on Liquefied Natural Gas (LNG) tankers as

well as LNG fueled vessels. This proposed ban is based on anecdotal evidence that sodium-based

agents are prone to caking and clogging, as well as the belief that they are less efficient than potassium

based agents. This ban would affect the US shipping industry.

CG-5PS plans to investigate the differences in sodium-based and potassium-based dry

chemical agents by testing combinations of Contractor-made raw, milled, sifted, weathered, with and

without additives, as well as commercially available off the shelf sodium-based and potassium-based

agents, to determine what, if any, technical basis exists for banning specific agents. It is of interest to

analyze these agents susceptibility to clogging and caking by using the industry consensus standards

International Standards Organization (ISO) 7202, Fire Protection — Fire Extinguishing Media —

Powder (2018 Edition) and Underwriters Laboratories (UL) 1254, Pre-Engineered Dry and Wet

Chemical Extinguishing System Units (2019 Edition), and UL 299, Dry Chemical Fire Extinguishers

(2018 Edition). It should be noted that the tests performed per UL 1254 and UL 299 were the same

specific methods required for dry chemical extinguishing agent. In UL 1254, these test procedures are

detailed in Section 51.2 and 51.3. In UL 299, these same procedures are detailed in Section 48.2 and

48.3. For simplicity, the rest of the report will only refer to UL 299.

It is also of interest to investigate the performance effects of dry chemical agents subjected to

thermal cycling and environmental conditioning. After evaluating specimens to ISO 7202 and UL

299, an assessment of the test methods will be conducted in order to identify if the standards adequately

predict the tendency of an agent to clog or cake in the marine environment.

After the preliminary testing of dry chemical agent properties, pool fire testing will be

conducted per ISO 7165, Fire-Fighting — Portable Fire Extinguishers — Performance and

Construction (2017 Edition) and UL 711, Rating and Fire Testing of Fire Extinguishers (2018

Edition). Testing will be conducted using both weathered and not weathered, commercially available

sodium and potassium-based fire extinguishing dry chemical systems as well as the Contractor made

dry chemical mixtures to evaluate their firefighting performance, as well as their caking, clogging, and

discharge characteristics.

Phase 1 testing per ISO 7202 and UL 299 was initiated on September 26, 2019, and completed

on November 26, 2019, by Southwest Research Institute’s (SwRI) Fire Technology Department

(FTD), located in San Antonio, Texas.


The results presented in this report apply only to the materials tested, in the manner tested,

and not to any similar materials or material combinations. This testing was conducted in accordance

with the relevant sections of the applicable standards and, to the best of our knowledge, it contains

no errors, omissions, or false statements.

2.0 TEST SPECIMENS

Sodium and potassium-based agents that were tested in Phase 1 are listed in Table 1 below.

Sodium bicarbonate (NaHCO3) and potassium bicarbonate (KHCO3) were used as the base of the dry

chemical mixtures. The considered test variables were presence of additives, sample

preparation/mixing methods (milling/sifting) and weathering of samples prior to testing. An entry of

“Yes” is colored green and an entry of “No” is colored yellow.

Table 1. Phase 1 Test Sample Matrix.

Base Sample (ID) % NaHCO3 % KHCO3

Additives

Milled/ Sifted? Weathered? % Clay % Silica

Sodi

um B

icar

bona

te (N

aHC

O3) Na1a 100 0 0 0 No No

Na1b 100 0 0 0 No Yes

Na2a 100 0 0 0 Yes No

Na2b 100 0 0 0 Yes Yes

Na3a 96 0 2 2 No No

Na3b 96 0 2 2 No Yes

Na4a 96 0 2 2 Yes No

Na4b 96 0 2 2 Yes Yes

Pota

ssiu

m B

icar

bona

te (K

HC

O3) K1a 0 100 0 0 No No

K1b 0 100 0 0 No Yes

K2a 0 100 0 0 Yes No

K2b 0 100 0 0 Yes Yes

K3a 0 96 2 2 No No

K3b 0 96 2 2 No Yes

K4a 0 96 2 2 Yes No

K4b 0 96 2 2 Yes Yes

SwRI procured the base dry chemical from Earthborn Elements. Both were Food and USP

pharmaceutical grade. For the additives, silica dioxide (CAS: 68611-44-9) and Attapulgite clay (CAS:

12174-11-7) were chosen based on a review of SDS information from several commercial products.

These were both procured from EastChem. Figure 1 shows a photograph of each of these materials.


Figure 1. Left: NaHCO3 Base, Center: KHCO3 Base, Right: Additives.

The samples were mixed in one of three ways depending on Table 1. For samples that did

not require milling or sifting per the matrix, they were simply mixed with a stand mixer. For samples

that were milled and sifted, a flour/grain style mill was used and subsequent to the milling, the sample

was sifted with an electric sieve/shaker appliance. Figure 2 shows a photograph of each of these

devices.

Figure 2. Left: Stand Mixer, Center: Flour/Grain Mill, Right: Sieve Shaker.

The purpose of the weathering of a subset of the samples was to evaluate if a given product

was more or less susceptible to clogging or caking when subjected to marine environmental conditions.

The weathered samples were conditioned in metal tin cans of a nominal 1-gal capacity. The

exposures were carried out with the lids off these sample containers. The environmental exposure

testing was performed by the Structural Dynamics group in the Mechanical Engineering Division at

SwRI. Figure 3 shows a photograph of the thermal chamber and salt fog apparatus used for this part

of testing.

In order to approximate the marine environment, two types of extended exposures were

imposed on the weathered samples. First, they were subjected to thermal cycling in accordance with

MIL-STD-810H, Environmental Engineering Considerations and Laboratory Tests. This test

consisted of 10 cycles, with each cycle having an 8 h dwell at -30°C and an 8 h dwell at +65°C. The

transition between temperatures was maintained to be no more than 3°C per minute to avoid thermal

shock conditions. Testing was initiated by heating the samples to 65 ºC at a rate of 2-3 ºC/min. The

temperature was held at 65 ºC for 8 h and then ramped down to -30 ºC at 2-3 ºC. This temperature


was held at -30 ºC for 8 h and the cycle was repeated 9 additional times. The total thermal exposure

testing took approximately 7 days and after completed, the samples were allowed to come to

equilibrium under standard temperature conditions (20-25 ºC). This exposure was completed on

October 3, 2019.

The day after thermal cycling was complete, the specimens were subjected to salt fog exposure

using ASTM B117-18, Standard Practice for Operating Salt Spray (Fog) Apparatus, as guidance.

This test involves exposure to a fog generated from 5% salt water solution (by mass) with a fallout

rate and pH that comply with the specification. The temperature in the exposure zone of the salt/fog

chamber is required to be 35 ± 2°C (95 ± 3°F). While ASTM B117 does not specify an exposure

duration, 240 h (10 days) is a common duration and was used for this testing. After the exposure was

completed, the samples were allowed to come to equilibrium under standard temperature conditions

(20-25 ºC). This exposure was completed on October 14, 2019. The sample container lids were

installed and the samples were transported back to the Fire Technology for subsequent ISO 7202 and

UL 299 testing, which was conducted over the following six weeks.

Figure 3. Left: Thermal Cycling Chamber, Right: Salt/Fog Test Apparatus.

3.0 TEST PROCEDURES

Testing of the dry chemical samples were conducted per ISO 7202 and UL 299 to assess

the propensity for a mixture to cake, flow freely, absorb moisture and repel water. In addition, tests

are ongoing to characterize each mixture sample using the methods outlined in ISO 11358-1 (2014

Edition), Plastics — Thermogravimetry (TG) of Polymers—Part 1: General Principles. This

standard provides procedures for using Differential Scanning Calorimetry (DSC) and

Thermogravimetric Analysis (TGA) in order to obtain material properties of a specimen. The

following subsections provide additional details about the various test methods.

3.1 ISO 7202

Sections 7 – 12 of ISO 7202 provide pass/fail criteria for each of the bench-scale test

methods for extinguisher powder in Sections 13.4 – 13.9. Each of the following subsections

provides additional details for the specific test methods utilized in this project.


3.1.1 Section 13.4 – Fluidity Test

The procedure requires that a 300 g specimen of powder be placed inside a glass fixture.

The glass container is fixed to the bracket and repeatedly turned over for 30 s. After this spinning

is finished, the time it takes for the powder to flow through the neck in the center of the glass

container is measured. The test is repeated 20 times for each specimen and three specimens were

tested for each sample ID. Per Section 7 of ISO 7202, the average flow time shall not exceed 8 s.

Figure 4 shows the glass fixture required for fluidity testing.

Figure 4. Left: Schematic of Fluidity Test Device, Right: Photograph of SwRI’s Fluidity Device.

3.1.2 Section 13.5 – Test for Resistance to Caking and Clumping

The procedure requires that an excess of powder be placed inside a Petri dish, which

measures approximately 70 mm diameter and is 10 mm high. The surface of the powder is made

flush with the rim of the dish with a pallet knife.

The Petri dish is placed in a desiccator for 24 h, maintained at 20 ± 5 ºC, that contains a

saturated sodium chloride solution, which provides approximately 75 % relative humidity. After

the desiccator exposure, the samples are moved into an oven maintained at 48 ± 3 ºC for an

additional 24-hr period. After the oven exposure, the samples are covered and allowed to cool for

1 h, after which time, the Petri dish is overturned on a clean sheet of paper for further evaluation.

The powder is allowed to slide into a 425 µm sieve such that any formed lumps are not

crushed. The sieve is shaken gently with horizontal revolving movements to separate the formed

lumps from free flowing powder without crushing the lumps.

A spatula is used to lift the lumps, drop them from a height of 200 ± 10 mm onto a clean

sheet of paper, which is placed on a hard surface. The process is repeated and any remaining powder

is sieved and any remaining lumps are dropped a second time.


Per Section 8 of ISO 7202, any lumps formed shall not be retained on the 425 µm sieve

after the lumps have been dropped and sieved twice. Figure 5 shows the desiccator and oven used

during testing.

Figure 5. Left: Desiccator with Salt Solution, Right: Oven used for Temperature Exposure.

3.1.3 Section 13.6 – Water Repellence Test

Samples are prepared in the same way in the same type of Petri dish as described in the

previous section. On three different areas of the powder surface, a drop of distilled water is applied

gently. The Petri dish is placed in the same desiccator as previously described for 2 h at 20 ± 5 ºC.

The Petri dish is removed and the drops are examined. Per Section 9 of ISO 7202, there shall be no

complete absorption of the water droplets into the powder. Figure 6 shows two photographs

illustrating complete absorption and no absorption.

Figure 6. Left: Samples that completely absorbed Water Droplets, Right: Samples that did not

completely absorb the Water Droplets.

3.1.4 Section 13.7 – Test Method for Moisture Content

The procedure requires that a 20 g specimen of powder be placed inside the same type of

Petri dish as previously described. The Petri dish is placed is a desiccator, with concentrated sulfuric

acid, for 48 h at a temperature of 20 ± 3 ºC. After removal of the Petri dish from the desiccator, the

sample is reweighed and the weight loss is calculated as a percentage of the original sample weight.

Per Section 10 of ISO 7202, the moisture content shall not exceed a mass fraction of 0.25%.


3.1.5 Section 13.9 – Moisture Absorption Testing

The procedure requires that a 10 g specimen of powder be placed inside the same type of

Petri dish as previously described. The sample is spread out so that it has a smooth surface and even

layer. The sample is placed in a desiccator containing 38.12% sulfuric acid at a temperature of

30 ºC for 48 h. Upon completion of the exposure, the sample is removed from the desiccator and

the weight is recorded. This is referred to as Weight A(60% RH). After the measurement, the sample

is placed in a desiccator containing a saturated solution of ammonium chloride at a temperature of

30 ºC for 48 h. Upon completion of this exposure, the sample is removed from the desiccator and

the weight is recorded. This is referred to as Weight B(80% RH). The rate of weight increase is

calculated per Equation 1 below. Per Section 12 of ISO 7202, the rate of weight increase (moisture

absorbance) shall be less than 2%.

𝑊𝑊𝑊𝑊𝑊𝑊𝑊𝑊ℎ𝑡𝑡 𝐵𝐵(80% 𝑅𝑅𝑅𝑅)−𝑊𝑊𝑊𝑊𝑊𝑊𝑊𝑊ℎ𝑡𝑡 𝐴𝐴(60% 𝑅𝑅𝑅𝑅)

𝑊𝑊𝑊𝑊𝑊𝑊𝑊𝑊ℎ𝑡𝑡 𝐴𝐴(60% 𝑅𝑅𝑅𝑅)= 𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀𝑀 𝐴𝐴𝐴𝐴𝑀𝑀𝑀𝑀𝑀𝑀𝐴𝐴𝑀𝑀𝑀𝑀𝑀𝑀𝐴𝐴 �%𝑤𝑤

𝑤𝑤� (Eq. 1)

3.2 UL 299

Section 48.1.1 of UL 299 stipulates that when subjected to the tests specified in 48.2.1 –

48.3.3, the dry chemical specimen shall be free flowing, except that should there be any tendency

to lump, harden, or cake, such portions shall be friable when dropped from a height of 100 mm (4 in)

onto a smooth, hard surface. Prior to the tests, all dry chemical samples are conditioned in a

desiccator containing anhydrous calcium chloride for 48 hours at room temperature. Each of the

following subsections provides additional details for the specific test methods utilized in this project.

3.2.1 Section 48.2 – Elevated Temperature Test

The procedure requires that a 150 g specimen of powder be placed inside seamless tinned

steel cups measuring approximately 75 mm (3 in) in diameter and 50 mm (2 in) deep with closely

fitting flanged covers. The specimens are then placed in an oven maintained at 60 ºC (140ºF). After

one week, the samples are removed from the oven, allowed to cool for three days and then examined

for evidence of caking. Any lumps present are to be dropped from a height of 100 mm (4 in) onto

a smooth hard surface to determine whether they are friable. Per Section 48.1.1 of UL 299, any

lumps present shall be friable. Figure 7 shows the tin cans for sample preparation and the oven used

for the testing.

Figure 7. Left: Samples in Tin Cans, Right: Oven for Elevated Temperature Test.


3.2.2 Section 48.3 – Hygroscopicity Test

The procedure requires that a 100 g specimen of powder be placed inside a standard 250-ml

beaker. The sample is placed in a chamber maintained at temperature of 21 ±3°C (70 ±5°F) and at

approximately 80 percent relative humidity. This relative humidity is obtained by maintaining a

saturated solution of ammonium chloride, containing an excess of undissolved crystals, at the

bottom of the chamber. After 2 days at 80 percent relative humidity, the 100 g sample is placed in

a chamber containing anhydrous calcium chloride for 2 days. This alternating cycle is continued

for three weeks, with observations made for caking of the dry chemical. Any lumps found are to be

dropped from a height of 100 mm (4 in) onto a smooth, hard surface to determine whether they are

friable. Per Section 48.1.1 of UL 299, any lumps present shall be friable. Figure 8 shows the

conditioning chamber and salts used for the exposures.

Figure 8. Left: Conditioning Chamber (1 of 2), Right: Conditioning Salts.

3.3 ISO 11358-1 – TGA Testing

This part of ISO 11358 specifies general conditions for the analysis of polymers using

thermogravimetric techniques. It is applicable to liquids or solids. Solid materials may be in the

form of pellets, granules or powders.

Thermogravimetry can be used to determine the temperature(s) and rate(s) of decomposition

of polymers, and to measure at the same time the amounts of volatile matter, additives and/or fillers

they contain. The thermogravimetric measurements may be carried out in dynamic mode (mass

change versus temperature or time under programmed conditions) or isothermal mode (mass change

versus time at constant temperature). Thermogravimetric measurements may also be carried out

using different testing atmospheres, e.g. to separate decomposition in an inert atmosphere from

oxidative degradation.

Most modern test equipment of this type can also be used to make energy measurements,

which are derived based on temperature rise of the instrument in specific locations (typically, at or

just under the sample cup). ISO 11358-1 makes reference to ISO 11357-1, Plastics — Differential

Scanning Calorimetry (DSC) — Part 1: General Principles, for this application.


For TG testing, the general procedure is as follows. A test specimen is heated at specified

rates with a controlled temperature program, and the change in mass is measured as a function of

temperature. During measurement the test specimen is held in a controlled inert atmosphere.

In general, the reactions which cause the mass of a test specimen to change are

decomposition or oxidation reactions or the volatilization of a component. The change in mass is

recorded as a thermogravimetric (TG) curve.

The change in mass of a material as a function of temperature and the extent of this change

are indicators of the thermal stability of the material. TG data can therefore be used to evaluate the

relative thermal stability of polymers of the same generic family and polymer-polymer or polymer-

additive interactions, using measurements made under the same test conditions.

It is also of note that TG data may be used for process control, process development and

material evaluation. Long-term thermal stability is a complex function of service and environmental

condition, therefore, TG data alone may not be able to describe the long-term thermal stability of a

polymer.

Figure 9 shows SwRI’s TGA/DSC apparatus, which is a Netzsch Model STA 449 F3

Jupiter.

Figure 9. SwRI’s TGA/DSC Test Apparatus.

4.0 TEST RESULTS

The following subsections provide results to date for each of the test methods discussed in

the previous section of this report. In the following sections summary test results tables, passing

results are highlighted green and failing results are highlighted yellow.

4.1 ISO 7202 – Section 13.4 – Fluidity Test

Three replicate samples were tested 20 times each per the method. Table 2 provides a

summary of the results and the averages of each replicate sample are reported. Several of the


samples did not flow through the fixture. For this type of result, an average flow time of 20 s was

assigned for comparison purposes and subsequent data analysis.

Table 2. Phase 1 Test Results – ISO 7202 Section 13.4.

Sample (ID)

Average Flow Time over 20 Trials per Replicate (s) Average Flow

Time (s) PASS/FAIL? RANK Replicate 1 Replicate 2 Replicate 3

Sodi

um B

icar

bona

te

(NaH

CO

3)

Na1a 10.69 9.09 9.41 9.73 FAIL 9 Na1b N/A N/A N/A 20.00 FAIL 12 Na2a 7.94 8.33 8.50 8.26 FAIL 8 Na2b N/A N/A N/A 20.00 FAIL 12 Na3a 7.02 6.69 6.99 6.90 PASS 6 Na3b 6.47 6.23 6.18 6.29 PASS 5 Na4a 13.11 12.97 12.16 12.74 FAIL 11 Na4b 8.22 8.03 8.07 8.10 FAIL 7

Pota

ssiu

m B

icar

bona

te

(KH

CO

3)

K1a 4.56 4.40 4.50 4.49 PASS 1 K1b N/A N/A N/A 20.00 FAIL 12 K2a N/A N/A N/A 20.00 FAIL 12 K2b N/A N/A N/A 20.00 FAIL 12 K3a 5.08 5.21 5.15 5.15 PASS 2 K3b 5.23 5.21 5.21 5.22 PASS 3 K4a 12.50 11.87 11.85 12.07 FAIL 10 K4b 5.42 5.48 5.59 5.50 PASS 9

Figure 10 shows the results from Table 2 in graphical form. The black dotted line depicts

the failure threshold stipulated in ISO 7202 (8 s). Six out of the sixteen samples met the test

requirements. The repeatability between replicates was good and in only one case were replicate

results on both sides of the pass/fail line. The presence of additives seemed to help the performance.

Overall, the weathered samples performed poorly compared to the non-weathered samples.

Figure 10. Left: Schematic of Fluidity Test Device, Right: Photograph of SwRI’s Fluidity Device.

0

2

4

6

8

10

12

14

16

18

20

Na1a Na1b Na2a Na2b Na3a Na3b Na4a Na4b K1a K1b K2a K2b K3a K3b K4a K4b

Ave

rage

Flo

w T

ime

(s)

Sample ID

ISO 7202 - Section 13.4 (Fluidity)

Dotted line denotes failurethreshold. Results inexcess of 8 s fail therequirements of this test.


4.2 ISO 7202 – Section 13.5 – Test for Resistance to Caking and Clumping

Table 3 shows the results for the sodium-based samples when tested per Section 13.5 of

ISO 7202. Table 4 shows the results for the potassium-based samples when tested per Section 13.5

of ISO 7202. Per Section 8 of ISO 7202, any lumps formed shall not be retained on the 425 µm

sieve after the lumps have been dropped from a height of 200 ± 10 mm and sieved twice.

Table 3. Phase 1 Test Results – ISO 7202 Section 13.5 (Sodium-Based Samples).

Sample (ID)

Observations after First Sieve/Drop Observations after Second Sieve/Drop PASS / FAIL?

Replicate 1 Replicate 2 Replicate 3 Replicate 1 Replicate 2 Replicate 3

Na1a

No caking, no lumps, fine powder, no

second sieve/drop required

same as replicate 1

same as replicate 1 and 2 N/A N/A N/A PASS

Na1b entire sample

caked together, only broke in half after drop

entire sample caked together,

broke into a couple of large

pieces after drop

entire sample caked together,

broke into a couple of large

pieces after drop

Same as after first drop



FAIL

Na2a

no caking, no lumps, fine powder, no


same as replicate 1


Na2b

entire sample caked together, did not break

apart at all after drop

same as replicate 1

same as replicate 1 and 2




FAIL

Na3a

seemed like silica dioxide formed very small lumps

that would not break apart

same as replicate 1


still same small lumps after

second sieve

same as replicate 1

same as replicate 1 and

2 FAIL

Na3b

mostly a very fine powder, some small masses left

after sieve/drop

same as replicate 1


still have some small lumps after second

sieve

same as replicate 1


2 FAIL

Na4a no caking, no lumping, no second sieve

required

same as replicate 1


Na4b fine powder, a few very small

masses after sieve/drop

same as replicate 1


still have some small lumps after second

sieve

same as replicate 1


2 FAIL


Table 4. Phase 1 Test Results – ISO 7202 Section 13.5 (Potassium-Based Samples).

Sample (ID)

Observations after First Sieve/Drop Observations after Second Sieve/Drop PASS / FAIL?

Replicate 1 Replicate 2 Replicate 3 Replicate 1 Replicate 2 Replicate 3

K1a some caking, small lumps

same as replicate 1


still remaining lumps after

second sieve/drop

same as replicate 1


2 FAIL

K1b sample is a wet sludge, sticking

together

same as replicate 1


yes, still same remaining

sludge

same as replicate 1


2 FAIL

K2a very heavy

caking, large lumps

same as replicate 1


still remaining lumps after

second sieve/drop

same as replicate 1


2 FAIL

K2b sample is a wet sludge, sticking

together

same as replicate 1


yes, still same remaining

sludge

same as replicate 1


2 FAIL

K3a

seemed like silica dioxide formed very small lumps

that would not break apart

same as replicate 1


still same small lumps after second

sieve

same as replicate 1


2 FAIL

K3b fine powder, lots of very

small masses after sieve/drop

same as replicate 1


yes, still remaining

small masses after second sieve/drop

same as replicate 1


2 FAIL

K4a

no caking, no lumping, no


same as replicate 1


K4b fine powder, lots of very

small masses after sieve/drop

same as replicate 1


yes, still remaining

small masses after second sieve/drop

same as replicate 1


2 FAIL

Four out of the sixteen samples met the test requirements. The repeatability between

replicates was good and in only one case were replicate results slightly different (Na1b), although

this didn’t affect the pass/fail result. The sodium-based samples (3 out of 8 passed) performed

slightly better than the potassium-based samples (1 out of 8 passed). Overall, the weathered samples

performed poorly compared to the non-weathered samples.

Figure 11 shows a photograph array of the results of this testing. These photographs, along

with the observations in Tables 3 and 4 are used to assign ranks to the sample results for future

analysis of data trends.


Na1a, Pass, Rank 1 Na1b, Fail, Rank 15 Na2a, Pass, Rank 1 Na2b, Fail, Rank 16

Na3a, Fail, Rank 5 Na3b, Fail, Rank 5 Na4a, Pass, Rank 1 Na4b, Fail, Rank 5

K1a, Fail, Rank 11 K1b, Fail, Rank 13 K2a, Fail, Rank 12 K2b, Fail, Rank 13

K3a, Fail, Rank 5 K3b, Fail, Rank 5 K4a, Pass, Rank 1 K4b, Fail, Rank 5

Figure 11. Photograph Array of Final Results for Testing per ISO 7202, Section 13.5.


4.3 ISO 7202 – Section 13.6 – Water Repellence Test

Table 5 provides the results of this testing. Three drops of distilled water are applied to the

surface of each sample. Per Section 9 of ISO 7202, there shall be no complete absorption of the

water droplets into the powder.

There were three basic types of performance in this test. The first kind of result was that

the drops immediately soaked into the sample and were completely absorbed. The second kind of

result was that the drops soaked into the sample slightly, but not completely. The third kind of result

was that the drops did not soak into the sample at all. These three types of result aided in assigning

rank to the results, described in the next section of this report.

For this testing, the presence of additives seemed to be the main driver of good performance.

Overall, the weathered samples performed slightly worse compared to the non-weathered samples,

but not to the point where it changed the pass/fail result for a given mixture.

Table 5. Phase 1 Test Results – ISO 7202 Section 13.6 (Water Repellence).

Sample ID

Are Drops Completely Absorbed by the Powder? PASS /

FAIL? Additional Comments Replicate 1 Replicate 2 Replicate 3

Na1a Yes Yes Yes FAIL drops immediately soaked into sample Na1b Yes Yes Yes FAIL drops immediately soaked into sample Na2a Yes Yes Yes FAIL drops immediately soaked into sample Na2b Yes Yes Yes FAIL drops immediately soaked into sample Na3a No No No PASS drops intact sitting on top of samples

Na3b No No No PASS drops seemed to soak into the sample a little bit, but not completely

Na4a No No No PASS drops intact sitting on top of samples

Na4b No No No PASS drops seemed to soak into the sample a little bit, but not completely

K1a Yes Yes Yes FAIL drops immediately soaked into sample K1b Yes Yes Yes FAIL drops immediately soaked into sample K2a Yes Yes Yes FAIL drops immediately soaked into sample K2b Yes Yes Yes FAIL drops immediately soaked into sample K3a No No No PASS drops intact sitting on top of samples

K3b No No No PASS drops seemed to soak into the sample a little bit, but not completely

K4a No No No PASS drops intact, but seemed to soak into sample slightly

K4b No No No PASS drops seemed to soak into the sample a little bit, but not completely

4.4 ISO 7202 – Section 13.7 – Test Method for Moisture Content

The procedure requires that a 20 g specimen of powder be placed inside a Petri dish, which

is placed is a desiccator, with concentrated sulfuric acid, for 48 h at a temperature of 20 ± 3 ºC.

After removal of the Petri dish from the desiccator, the sample is reweighed and the weight loss is


calculated as a percentage of the original sample weight. Per Section 10 of ISO 7202, the moisture

content shall not exceed a mass fraction of 0.25%.

Table 6 provides the results of this testing. Figure 12 shows this data graphically and Figure

13 shows the same data, zoomed in on the failure threshold of a 0.25% moisture content mass

fraction, which is depicted by a black dotted line.

All of the weathered samples had a much higher moisture content than the non-weathered

samples, which is understanding considering they were exposed to salt/fog conditions with the lids

of the batch containers removed. For the non-weathered specimens, the potassium-based samples

exhibited a lower moisture content than the sodium-based samples. Also, the milling/sifting process

for the sodium-based samples seemed to aerate the specimens slightly, which seemed to impact the

ability for the water to be absorbed into the powder (e.g., compare Na1a to Na2a or Na3a to Na4a).

This effect was not seen for the potassium-based samples.

Table 6. Phase 1 Test Results – ISO 7202 Section 13.7 (Moisture Content). Initial Mass (g) Final Mass (g) Mass Fraction (%)

Sample ID #1 # 2 # 3 #1 # 2 # 3 #1 # 2 # 3

Average Mass

Fraction (%)

PASS / FAIL?

Na1a 20.000 20.000 20.000 20.000 20.000 20.000 0.000 0.000 0.000 0.000 PASS Na1b 20.001 20.001 20.001 19.242 19.219 19.257 3.795 3.910 3.720 3.808 FAIL Na2a 20.000 20.000 20.000 19.991 20.000 19.994 0.045 0.000 0.030 0.025 PASS Na2b 20.001 20.001 20.001 19.091 19.380 19.305 4.550 3.105 3.480 3.711 FAIL Na3a 20.000 20.000 20.000 19.985 19.994 19.989 0.075 0.030 0.055 0.054 PASS Na3b 20.001 20.001 20.001 19.650 19.762 19.720 1.755 1.195 1.405 1.452 FAIL Na4a 20.000 20.000 20.000 19.964 19.981 19.978 0.180 0.095 0.110 0.128 PASS Na4b 20.001 20.001 20.001 19.792 19.682 19.681 1.045 1.595 1.600 1.413 FAIL K1a 20.000 20.000 20.000 20.000 20.000 20.000 0.000 0.000 0.000 0.000 PASS K1b 20.000 20.001 20.001 18.027 18.122 18.313 9.865 9.395 8.440 9.233 FAIL K2a 20.000 20.000 20.000 20.000 20.000 20.000 0.000 0.000 0.000 0.000 PASS K2b 20.001 20.001 20.000 18.142 18.368 18.347 9.295 8.165 8.265 8.575 FAIL K3a 20.000 20.000 20.000 20.000 20.000 20.000 0.000 0.000 0.000 0.000 PASS K3b 20.001 20.001 20.001 19.753 19.755 19.738 1.240 1.230 1.315 1.262 FAIL K4a 20.000 20.000 20.000 20.000 20.000 20.000 0.000 0.000 0.000 0.000 PASS K4b 20.001 20.001 20.001 19.204 19.150 19.221 3.985 4.255 3.900 4.046 FAIL


Figure 12. Graphical Results of ISO 7202, Section 13.7 Testing.

Figure 13. Graphical Results of ISO 7202, Section 13.7 Testing (Zoomed in on Y-Axis).

4.5 ISO 7202 – Section 13.9 – Moisture Absorption Testing

The procedure requires that a 10 g specimen of powder be placed inside a Petri dish and

spread out so that it has a smooth surface and even layer. The sample is alternately placed in a 60%

RH and 80% RH atmosphere and weighed after each exposure. The moisture absorbance is defined

as the percent difference of these weights using the 60% value as the expected value. Per Section

12 of ISO 7202, the rate of weight increase (moisture absorbance) shall be less than 2%.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50


Ave

rage

Wat

er M

ass F

ract

ion

(%)

Sample ID

ISO 7202 - Section 13.7 (Moisture Content)


Table 7 shows the results of this testing. All the samples passed by a wide margin. The

limit is 2% moisture absorption and the closest material to that limit was K1a at 0.83%. This could

imply that this specific test method may not be as useful as some of the other methods in

differentiating performance between dry chemical powders.

On average, the sodium-based samples performed better than the potassium-based samples

and that was especially the case for the samples with additives.

Table 7. Phase 1 Test Results – ISO 7202 Section 13.9 (Moisture Absorption).

Sample ID

Moisture Absorption (% w/w) Average Moisture

Absorption (%)

PASS / FAIL? RANK

Replicate 1 Replicate 2 Replicate 3

Na1a 0.00 0.40 0.40 0.27 PASS 5 Na1b 0.60 0.30 0.60 0.50 PASS 12 Na2a 0.00 0.40 0.60 0.33 PASS 6 Na2b 0.40 0.50 0.30 0.40 PASS 8 Na3a 0.10 0.10 0.00 0.07 PASS 3 Na3b 0.10 0.00 0.10 0.07 PASS 1 Na4a 0.10 0.10 0.00 0.07 PASS 3 Na4b 0.00 0.10 0.10 0.07 PASS 1 K1a 0.90 0.90 0.70 0.83 PASS 16 K1b 0.50 0.50 0.60 0.53 PASS 14 K2a 0.10 0.60 0.70 0.47 PASS 11 K2b 0.60 0.50 0.50 0.53 PASS 13 K3a 0.30 0.50 0.30 0.37 PASS 7 K3b 0.50 0.80 0.70 0.67 PASS 15 K4a 0.40 0.40 0.40 0.40 PASS 9 K4b 0.70 0.30 0.40 0.47 PASS 5


Figure 14. Graphical Results of ISO 7202, Section 13.9 Testing.

4.6 UL 299 – Section 48.2 – Elevated Temperature Test

The procedure requires that a 150 g specimen of powder be placed inside seamless tinned

steel cups measuring approximately 75 mm (3 in) in diameter and 50 mm (2 in) deep with closely

fitting flanged covers. The specimens are then placed in an oven maintained at 60 ºC (140ºF). After

one week, the samples are removed from the oven, allowed to cool for three days and then examined

for evidence of caking. Any lumps present are to be dropped from a height of 100 mm (4 in) onto

a smooth hard surface to determine whether they are friable. Per Section 48.1.1 of UL 299, any

lumps present shall be friable.

This test method is similar in principle to Section 13.5 of ISO 7202. However, the exposure

is longer and at a higher temperature in the standard UL test, as compared to the ISO test. Also, the

drop test in this UL method is from 100 mm (4 in.), whereas the drop is from 200 mm (8 in.) in the

ISO test method. Finally, the UL method doesn’t specify a sieve for friability quantification and

only says that the lumps should be friable, which is interpreted that they break apart when dropped,

not that they break to a specific particle size when dropped.


UL 299. Table 9 shows the results for the potassium-based samples when tested per Section 48.2

of UL 299.

Four out of the sixteen samples met the test requirements. The repeatability between

replicates was good and in only one case were replicate results slightly different (Na4b and K1a),

although this didn’t affect the pass/fail result. The sodium-based samples (3 out of 8 passed)

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90


Moi

stur

e A

bsor

ptio

n (%

)

Sample ID

ISO 7202 - Section 13.9 (Moisture Absorption)


performed slightly better than the potassium-based samples (1 out of 8 passed). Overall, the

weathered samples performed poorly compared to the non-weathered samples.




Table 8. Phase 1 Test Results – UL 299 Section 48.2 (Sodium-Based Samples).

Sample (ID)

Observations after Temperature Exposure

Any Remaining “Non-Friable” Lumps after Drop Test PASS /

FAIL? Replicate 1 Replicate 2 Replicate 3 Replicate 1 Replicate 2 Replicate 3

Na1a

some caking throughout,

lots of lumps, small to big in

size

same as replicate 1


Yes, several non-friable

lumps left after drop test

same as replicate 1


2 FAIL

Na1b lots of masses

throughout sample, lots of

caking

same as replicate 1




same as replicate 1


2 FAIL

Na2a

some caking throughout,

lots of lumps, small to big in

size

same as replicate 1




same as replicate 1


2 FAIL

Na2b lots of masses

throughout sample, lots of

caking

same as replicate 1




same as replicate 1


2 FAIL

Na3a

no caking, but seemed to have small masses of

the silica dioxide on top

same as replicate 1

same as replicate 1 and 2 No lumps same as

replicate 1


2 PASS

Na3b

very small masses of silica dioxide on top, no caking other

than those masses

same as replicate 1


no lumps, just these very tiny SiO2 masses

same as replicate 1


2 PASS

Na4a very little caking

same as replicate 1


No, remaining lumps, they

completely fell apart

same as replicate 1


2 PASS

Na4b

very little caking, a few

masses throughout

sample

same as replicate 1




same as replicate 1

similar to replicate 1 and

2, but fewer lumps

remaining

FAIL


Table 9. Phase 1 Test Results – UL 299 Section 48.2 (Potassium-Based Samples).

Sample (ID)




K1a some caking, mostly small

lumps

some caking, mostly small lumps, but some larger lumps too

some caking, mostly small

lumps, but some larger lumps too

Yes, small lumps

remaining

same as replicate 1


2 FAIL

K1b

very wet sample with

consistency of sludge/mud, orange-pink

color

same as replicate 1


No defined lumps to drop, sample is too

wet

same as replicate 1


2 FAIL

K2a heavy caking, entire sample

consists of lumps

same as replicate 1


Yes, little to no breaking apart after drop test

same as replicate 1


2 FAIL

K2b

very wet sample with

consistency of sludge/mud, orange-pink

color

same as replicate 1


No defined lumps to drop, sample is too

wet

same as replicate 1


2 FAIL

K3a almost no

caking, very few small

lumps

same as replicate 1


Yes, no breaking apart of any of the small lumps

same as replicate 1


2 FAIL

K3b small masses throughout,

look like SiO2 lumps

same as replicate 1


yes, small SiO2 lumps

did not break apart

same as replicate 1


2 FAIL

K4a no caking no caking no caking no lumps same as replicate 1


2 PASS

K4b small masses throughout,

look like SiO2 lumps

same as replicate 1


yes, small SiO2 lumps

did not break apart

same as replicate 1


2 FAIL






Figure 15. Photograph Array of Final Results for Testing per UL 299, Section 48.2.


4.7 UL 299 – Section 48.3 – Hygroscopicity Test

The procedure requires that a 100 g specimen of powder be placed inside a standard 250-ml

beaker. The sample is placed in a chamber maintained at temperature of 21 ±3°C (70 ±5°F) and at

approximately 80 percent relative humidity. This relative humidity is obtained by maintaining a

saturated solution of ammonium chloride, containing an excess of undissolved crystals, at the

bottom of the chamber. After 2 days at 80 percent relative humidity, the 100 g sample is placed in

a chamber containing anhydrous calcium chloride for 2 days. This alternating cycle is continued

for three weeks, with observations made for caking of the dry chemical. Any lumps found are to be

dropped from a height of 100 mm (4 in) onto a smooth, hard surface to determine whether they are

friable. Per Section 48.1.1 of UL 299, any lumps present shall be friable.

This test method is similar in principle to Section 13.9 of ISO 7202. However, the exposure

is slightly different. In section 13.9 of ISO 7202, there is only one cycle of 80% and 60% RH for a

period of 2 days each. In the UL test, the cycle is repeated for 3 weeks. Also, while the method

doesn’t specify the environment that anhydrous calcium chloride provides in equilibrium, this

information is readily available in the literature and ranges from ~15-30 % RH at the test temperature

range. So, the UL test specifies a more extreme RH range (~20 – 80 % RH). However, since it is

not required to measure mass changes during the exposure, it is difficult to compare the results

between methods. This may be something to consider in Phase 2 of the project.

Also, the drop test in this UL method is from 100 mm (4 in.), whereas the drop is from

200 mm (8 in.) in the ISO test method. Finally, the UL method doesn’t specify a sieve for friability

quantification and only says that the lumps should be friable, which is interpreted that they break

apart when dropped, not that they break to a specific particle size when dropped.


UL 299. Table 11 shows the results for the potassium-based samples when tested per Section 48.2

of UL 299.


Table 10. Phase 1 Test Results – UL 299 Section 48.3 (Sodium-Based Samples).

Sample (ID)




Na1a some caking throughout,

small masses throughout

same as replicate 1

same as replicate 1 and 2 No No No PASS

Na1b heavy caking throughout

same as replicate 1

same as replicate 1 and 2 Yes Yes Yes FAIL

Na2a some caking throughout,


same as replicate 1

same as replicate 1 and 2 No No No PASS

Na2b heavy caking throughout

same as replicate 1


Na3a lots of silica

dioxide masses on top, no

visible caking

same as replicate 1


No lumps to test

No lumps to test

No lumps to test PASS

Na3b some caking throughout,


same as replicate 1


Na4a no visible caking

same as replicate 1


No lumps to test

No lumps to test


Na4b lots of masses,

caking throughout

same as replicate 1



Table 11. Phase 1 Test Results – UL 299 Section 48.3 (Potassium-Based Samples).

Sample (ID)




K1a caking

throughout, a couple of

visible lumps

same as replicate 1


K1b heavy caking throughout

same as replicate 1


K2a heavy caking throughout

same as replicate 1


K2b heavy caking throughout

same as replicate 1


K3a wet spots,

small masses on top of sample

same as replicate 1


No lumps to test

No lumps to test


K3b small masses throughout, little caking

same as replicate 1


K4a No visible caking

same as replicate 1


No lumps to test

No lumps to test


K4b small masses throughout, little caking

same as replicate 1


Six out of the sixteen samples met the test requirements. The repeatability between

replicates was good and all the replicate results were qualitatively the same. The sodium-based

samples (4 out of 8 passed) performed slightly better than the potassium-based samples (2 out of 8

passed). Overall, the weathered samples performed poorly compared to the non-weathered samples.









Figure 16. Photograph Array of Final Results for Testing per UL 299, Section 48.3.


4.8 ISO 11358-1 (TGA Testing)

This testing has started, but is not complete. An initial series of screening runs were

performed to investigate the optimal ramp rate and temperature range for the samples. Ramp rates

of 5, 10, and 20 K/min were evaluated and 5 K/min was selected for the remaining tests. A slower

ramp rate ensures that phase transitions are measurable, but this affects the required test duration

for a given sample. However, for the faster ramp rates, the second phase transition for samples with

additives was not repeatable. For samples with additives, it was found that it would be necessary to

run the tests up to approximately 1000 ºC, whereas for the samples without additives, tests could be

terminated after 400 ºC.

Figure 17 and Figure 18 show the preliminary results for the K1a and Na1a samples,

respectively. Figure 19 shows preliminary results for Na3a samples.

For the limited replicate tests that have been performed to date, the repeatability is good.

The initial major transition temperature is approximately the same for potassium-based samples

(~120 – 140 ºC) and sodium-based samples (~100 – 120 ºC). For samples with additives, the onset

of this second transition appears to start at 750 – 800 ºC, but this will be confirmed after testing is

complete.

Figure 17. TGA/DSC Test Results for K1a at 5 K/min Ramp Rate.


Figure 18. TGA/DSC Test Results for Na1a at 5 K/min Ramp Rate.

Figure 19. TGA/DSC Test Results for Na3a at 5 K/min Ramp Rate.


5.0 DATA ANALYSIS

A total of 1,248 test trials (960 trials for Fluidity Test) have been conducted between the

ISO 7202 and UL 299 testing to date. Some of the data is quantitative (e.g., fluidity test, moisture

content, moisture absorption) and some of the data is qualitative (e.g., caking and clumping tests,

water repellence, hygroscopicity). With such a large amount of data, which is not all easy to sort

quantitatively, it was necessary to develop a methodology for comparing the data across test

variables and test methods.

The initial approach to that problem is to assign ranking values to each sample ID for each

test method and to sum these up and plot them in different ways to try to determine which materials

perform best and which test variables seem to drive the results. For test methods that have

quantitative results, the ranking is straightforward (i.e. lower ranking = better result) and these tests

were given a value between 1 and 16 depending on severity of pass/fail. This was the case for

Sections 13.4, 13.7, and 13.9 of ISO 7202. For the remaining test methods (Section 13.5 and 13.6

of ISO 7202 and the UL 299), some judgement was required based on a comparative analysis of the

test observations and the photographs. These rankings helped separate performance between

samples that otherwise were only initially placed into one of two categories (i.e., pass or fail).

Tables 12 and 13 show the pass/fail results for all the samples when tested per ISO 7202

and UL 299, respectively. It can be seen that not a single sample met the requirements of all seven

test methods. For ISO 7202 only, none of the samples passed all the tests, but four of them (Na3a,

Na4a, K3a and K4a) met the requirements of four of the five of the procedures. For UL 299, there

were three samples (Na3a, Na4a and K4a) that met the requirements of both procedures.

Tables 14 and 15 show a summary of all the rankings for ISO 7202 and UL 299,

respectively. The Pass Rank is based on the results in Tables 12 and 13, the Section number rankings

reflect how each sample did in each procedure and the total rank score is the sum of all the ranks

for a given sample. The total rank score column is shaded in a gradient that reflects the ranking.

The lightest shading is the best (lowest) ranking and the shading gets darker as the ranking increases

in value. Figure 20 shows this data graphically in a stacked histogram. Figures 21 and 22 show the

same data for only the non-weathered and weathered samples, respectively.


Table 12. Phase 1 Test Results – Summary of Pass/Fail Results for ISO 7202.

ISO 7202 Test Section Number

Sample ID

13.4 - Fluidity Test

13.5 – Caking and Clumping

13.6 – Water

Repellence

13.7 - Moisture Content

13.9 - Moisture

Absorption Na1a FAIL PASS FAIL PASS PASS Na1b FAIL FAIL FAIL FAIL PASS Na2a FAIL PASS FAIL PASS PASS Na2b FAIL FAIL FAIL FAIL PASS Na3a PASS FAIL PASS PASS PASS Na3b PASS FAIL PASS FAIL PASS Na4a FAIL PASS PASS PASS PASS Na4b FAIL FAIL PASS FAIL PASS K1a PASS FAIL FAIL PASS PASS K1b FAIL FAIL FAIL FAIL PASS K2a FAIL FAIL FAIL PASS PASS K2b FAIL FAIL FAIL FAIL PASS K3a PASS FAIL PASS PASS PASS K3b PASS FAIL PASS FAIL PASS K4a FAIL PASS PASS PASS PASS K4b PASS FAIL PASS FAIL PASS

Table 13. Phase 1 Test Results – Summary of Pass/Fail Results for UL 299.

UL 299 Test Section Number

Sample ID 48.2 - Elevated Temp 48.3 - Hygroscopicity

Na1a FAIL PASS Na1b FAIL FAIL Na2a FAIL PASS Na2b FAIL FAIL Na3a PASS PASS Na3b PASS FAIL Na4a PASS PASS Na4b FAIL FAIL K1a FAIL FAIL K1b FAIL FAIL K2a FAIL FAIL K2b FAIL FAIL K3a FAIL PASS K3b FAIL FAIL K4a PASS PASS K4b FAIL FAIL


Table 14. Phase 1 Test Results – Summary of Test Result Rankings – ISO 7202.

Sample ID

PASS RANK

13.4 RANK

13.5 RANK

13.6 RANK

13.7 RANK

13.9 RANK

TOTAL RANK

SCORE Na1a 5 9 1 9 1 5 30

Na1b 13 12 15 9 12 12 73

Na2a 5 8 1 9 5 6 34

Na2b 13 12 16 9 10 8 68

Na3a 1 6 4 1 5 3 20

Na3b 5 5 4 5 8 1 28

Na4a 1 11 1 1 5 3 22

Na4b 11 7 4 5 6 1 34

K1a 5 1 11 9 1 16 43

K1b 13 12 13 9 7 14 68

K2a 11 12 12 9 3 11 58

K2b 13 12 13 9 5 13 65

K3a 1 2 4 1 1 7 16

K3b 5 3 4 5 2 15 34

K4a 1 10 1 1 1 9 23

K4b 5 4 4 5 1 10 29

Table 15. Phase 1 Test Results – Summary of Test Result Rankings – UL 299.

Sample ID

PASS RANK

48.2 RANK

48.3 RANK

TOTAL RANK SCORE

Na1a 4 10 5 19

Na1b 8 10 11 29

Na2a 4 10 5 19

Na2b 8 10 11 29

Na3a 1 1 1 3

Na3b 4 3 9 16

Na4a 1 3 1 5

Na4b 8 8 10 26

K1a 8 8 13 29

K1b 8 15 13 36

K2a 8 10 13 31

K2b 8 15 13 36

K3a 4 5 1 10

K3b 8 5 7 20

K4a 1 1 1 3

K4b 8 5 7 20


Figure 20. Summary of Stacked Total Rank Scores for All Samples.

Figure 21. Summary of Stacked Total Rank Scores for Non-Weathered Specimens.


Figure 22. Summary of Stacked Total Rank Scores for Weathered Specimens.

Table 16 organizes the total rank values by test variable. Figure 23 shows this data

graphically. The two most important test variables seem to be the presence of additives and if the

sample was weathered.

Table 16. Phase 1 Test Results – Summary of Ranking Results by Test Variable.

Agent Base Weathering? Additives? Milling /

Sifting?

TOTAL by Base

(Na or K)

TOTAL by Weathering

TOTAL by

Additives

TOTAL by

Milling / Sifting

Na Weathered Additives Milling / Sifting 417 557 283 459

K Non-Weathered

No Additives

No Milling / Sifting

480 340 614 438


Figure 23. Summary of Rank Scores Organized by Test Variable.

6.0 NEXT STEPS

The project is ongoing and the next steps over the next few months include the following:

1. Testing will be completed per ISO 11358-1 for all materials discussed in this report

(i.e., contractor-made sodium and potassium-based dry chemical mixtures).

2. Data analysis will continue on the current results, with a specific emphasis on

investigating and comparing each test procedure between each test method (ISO 7202

and UL 199).

3. Phase 2 of the project will commence, which includes the following tasks:

a. Additional ISO 7202 and UL 299 testing of commercial products (i.e.,

commercial off the shelf sodium, potassium and monoammonium phosphate

based dry chemical agents),

b. Additional ISO 7202 and UL 299 testing of sample mixture combinations

from current test matrix,

c. Fire extinguishing tests on the Phase 2 materials per ISO 7165 and UL 711,

which are portable fire extinguisher test methods used internationally and in

the United States of America, respectively.

___________

sub-committee on ship systems and equipment original

Documents