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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 Page 2
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.
***
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
United States Coast Guard 3 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 4 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 5 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 6 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 7 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 8 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 9 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 10 SwRI Project No.: 01.24804.01.001
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%.
United States Coast Guard 11 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 12 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 13 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 14 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 15 SwRI Project No.: 01.24804.01.001
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
Same as after first drop
Same as after first drop
FAIL
Na2a
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
Na2b
entire sample caked together, did not break
apart at all after drop
same as replicate 1
same as replicate 1 and 2
Same as after first drop
Same as after first drop
Same as after first drop
FAIL
Na3a
seemed like silica dioxide formed very small lumps
that would not break apart
same as replicate 1
same as replicate 1 and 2
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
same as replicate 1 and 2
still have some small lumps after second
sieve
same as replicate 1
same as replicate 1 and
2 FAIL
Na4a no caking, no lumping, no second sieve
required
same as replicate 1
same as replicate 1 and 2 N/A N/A N/A PASS
Na4b fine powder, a few very small
masses after sieve/drop
same as replicate 1
same as replicate 1 and 2
still have some small lumps after second
sieve
same as replicate 1
same as replicate 1 and
2 FAIL
United States Coast Guard 16 SwRI Project No.: 01.24804.01.001
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
same as replicate 1 and 2
still remaining lumps after
second sieve/drop
same as replicate 1
same as replicate 1 and
2 FAIL
K1b sample is a wet sludge, sticking
together
same as replicate 1
same as replicate 1 and 2
yes, still same remaining
sludge
same as replicate 1
same as replicate 1 and
2 FAIL
K2a very heavy
caking, large lumps
same as replicate 1
same as replicate 1 and 2
still remaining lumps after
second sieve/drop
same as replicate 1
same as replicate 1 and
2 FAIL
K2b sample is a wet sludge, sticking
together
same as replicate 1
same as replicate 1 and 2
yes, still same remaining
sludge
same as replicate 1
same as replicate 1 and
2 FAIL
K3a
seemed like silica dioxide formed very small lumps
that would not break apart
same as replicate 1
same as replicate 1 and 2
still same small lumps after second
sieve
same as replicate 1
same as replicate 1 and
2 FAIL
K3b fine powder, lots of very
small masses after sieve/drop
same as replicate 1
same as replicate 1 and 2
yes, still remaining
small masses after second sieve/drop
same as replicate 1
same as replicate 1 and
2 FAIL
K4a
no caking, no lumping, no
second sieve/drop required
same as replicate 1
same as replicate 1 and 2 N/A N/A N/A PASS
K4b fine powder, lots of very
small masses after sieve/drop
same as replicate 1
same as replicate 1 and 2
yes, still remaining
small masses after second sieve/drop
same as replicate 1
same as replicate 1 and
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.
United States Coast Guard 17 SwRI Project No.: 01.24804.01.001
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.
United States Coast Guard 18 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 19 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 20 SwRI Project No.: 01.24804.01.001
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
Na1a Na1b Na2a Na2b Na3a Na3b Na4a Na4b K1a K1b K2a K2b K3a K3b K4a K4b
Ave
rage
Wat
er M
ass F
ract
ion
(%)
Sample ID
ISO 7202 - Section 13.7 (Moisture Content)
United States Coast Guard 21 SwRI Project No.: 01.24804.01.001
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
United States Coast Guard 22 SwRI Project No.: 01.24804.01.001
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.
Table 8 shows the results for the sodium-based samples when tested per Section 48.2 of
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
Na1a Na1b Na2a Na2b Na3a Na3b Na4a Na4b K1a K1b K2a K2b K3a K3b K4a K4b
Moi
stur
e A
bsor
ptio
n (%
)
Sample ID
ISO 7202 - Section 13.9 (Moisture Absorption)
United States Coast Guard 23 SwRI Project No.: 01.24804.01.001
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 15 shows a photograph array of the results of this testing. These photographs, along
with the observations in Tables 8 and 9 are used to assign ranks to the sample results for future
analysis of data trends.
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
same as replicate 1 and 2
Yes, several non-friable
lumps left after drop test
same as replicate 1
same as replicate 1 and
2 FAIL
Na1b lots of masses
throughout sample, lots of
caking
same as replicate 1
same as replicate 1 and 2
Yes, several non-friable
lumps left after drop test
same as replicate 1
same as replicate 1 and
2 FAIL
Na2a
some caking throughout,
lots of lumps, small to big in
size
same as replicate 1
same as replicate 1 and 2
Yes, several non-friable
lumps left after drop test
same as replicate 1
same as replicate 1 and
2 FAIL
Na2b lots of masses
throughout sample, lots of
caking
same as replicate 1
same as replicate 1 and 2
Yes, several non-friable
lumps left after drop test
same as replicate 1
same as replicate 1 and
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
same as replicate 1 and
2 PASS
Na3b
very small masses of silica dioxide on top, no caking other
than those masses
same as replicate 1
same as replicate 1 and 2
no lumps, just these very tiny SiO2 masses
same as replicate 1
same as replicate 1 and
2 PASS
Na4a very little caking
same as replicate 1
same as replicate 1 and 2
No, remaining lumps, they
completely fell apart
same as replicate 1
same as replicate 1 and
2 PASS
Na4b
very little caking, a few
masses throughout
sample
same as replicate 1
same as replicate 1 and 2
Yes, several non-friable
lumps left after drop test
same as replicate 1
similar to replicate 1 and
2, but fewer lumps
remaining
FAIL
United States Coast Guard 24 SwRI Project No.: 01.24804.01.001
Table 9. Phase 1 Test Results – UL 299 Section 48.2 (Potassium-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
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
same as replicate 1 and
2 FAIL
K1b
very wet sample with
consistency of sludge/mud, orange-pink
color
same as replicate 1
same as replicate 1 and 2
No defined lumps to drop, sample is too
wet
same as replicate 1
same as replicate 1 and
2 FAIL
K2a heavy caking, entire sample
consists of lumps
same as replicate 1
same as replicate 1 and 2
Yes, little to no breaking apart after drop test
same as replicate 1
same as replicate 1 and
2 FAIL
K2b
very wet sample with
consistency of sludge/mud, orange-pink
color
same as replicate 1
same as replicate 1 and 2
No defined lumps to drop, sample is too
wet
same as replicate 1
same as replicate 1 and
2 FAIL
K3a almost no
caking, very few small
lumps
same as replicate 1
same as replicate 1 and 2
Yes, no breaking apart of any of the small lumps
same as replicate 1
same as replicate 1 and
2 FAIL
K3b small masses throughout,
look like SiO2 lumps
same as replicate 1
same as replicate 1 and 2
yes, small SiO2 lumps
did not break apart
same as replicate 1
same as replicate 1 and
2 FAIL
K4a no caking no caking no caking no lumps same as replicate 1
same as replicate 1 and
2 PASS
K4b small masses throughout,
look like SiO2 lumps
same as replicate 1
same as replicate 1 and 2
yes, small SiO2 lumps
did not break apart
same as replicate 1
same as replicate 1 and
2 FAIL
United States Coast Guard 25 SwRI Project No.: 01.24804.01.001
Na1a, Pass, Rank 10 Na1b, Fail, Rank 10 Na2a, Pass, Rank 10 Na2b, Fail, Rank 10
Na3a, Pass, Rank 1 Na3b, Fail, Rank 3 Na4a, Pass, Rank 3 Na4b, Fail, Rank 8
K1a, Fail, Rank 8 K1b, Fail, Rank 15 K2a, Fail, Rank 10 K2b, Fail, Rank 15
K3a, Fail, Rank 5 K3b, Fail, Rank 5 K4a, Pass, Rank 1 K4b, Fail, Rank 5
Figure 15. Photograph Array of Final Results for Testing per UL 299, Section 48.2.
United States Coast Guard 26 SwRI Project No.: 01.24804.01.001
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.
Table 10 shows the results for the sodium-based samples when tested per Section 48.2 of
UL 299. Table 11 shows the results for the potassium-based samples when tested per Section 48.2
of UL 299.
United States Coast Guard 27 SwRI Project No.: 01.24804.01.001
Table 10. Phase 1 Test Results – UL 299 Section 48.3 (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,
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,
small masses throughout
same as replicate 1
same as replicate 1 and 2 No No No PASS
Na2b heavy caking throughout
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
Na3a lots of silica
dioxide masses on top, no
visible caking
same as replicate 1
same as replicate 1 and 2
No lumps to test
No lumps to test
No lumps to test PASS
Na3b some caking throughout,
small masses throughout
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
Na4a no visible caking
same as replicate 1
same as replicate 1 and 2
No lumps to test
No lumps to test
No lumps to test PASS
Na4b lots of masses,
caking throughout
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
United States Coast Guard 28 SwRI Project No.: 01.24804.01.001
Table 11. Phase 1 Test Results – UL 299 Section 48.3 (Potassium-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
K1a caking
throughout, a couple of
visible lumps
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
K1b heavy caking throughout
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
K2a heavy caking throughout
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
K2b heavy caking throughout
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
K3a wet spots,
small masses on top of sample
same as replicate 1
same as replicate 1 and 2
No lumps to test
No lumps to test
No lumps to test PASS
K3b small masses throughout, little caking
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
K4a No visible caking
same as replicate 1
same as replicate 1 and 2
No lumps to test
No lumps to test
No lumps to test PASS
K4b small masses throughout, little caking
same as replicate 1
same as replicate 1 and 2 Yes Yes Yes FAIL
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 shows a photograph array of the results of this testing. These photographs, along
with the observations in Tables 10 and 11 are used to assign ranks to the sample results for future
analysis of data trends.
United States Coast Guard 29 SwRI Project No.: 01.24804.01.001
Na1a, Pass, Rank 5 Na1b, Fail, Rank 11 Na2a, Pass, Rank 5 Na2b, Fail, Rank 11
Na3a, Pass, Rank 1 Na3b, Fail, Rank 9 Na4a, Pass, Rank 1 Na4b, Fail, Rank 10
K1a, Fail, Rank 13 K1b, Fail, Rank 13 K2a, Fail, Rank 13 K2b, Fail, Rank 13
K3a, Fail, Rank 1 K3b, Fail, Rank 7 K4a, Pass, Rank 1 K4b, Fail, Rank 7
Figure 16. Photograph Array of Final Results for Testing per UL 299, Section 48.3.
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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.
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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.
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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.
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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
United States Coast Guard 34 SwRI Project No.: 01.24804.01.001
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
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Figure 20. Summary of Stacked Total Rank Scores for All Samples.
Figure 21. Summary of Stacked Total Rank Scores for Non-Weathered Specimens.
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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
United States Coast Guard 37 SwRI Project No.: 01.24804.01.001
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.
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