Bench Tests for Characterizing Type X Special Fire Resistant

Gypsum Board –Repeatability & Reproducibility

Paul H Shipp, PhD, PE and Qiang Yu, PhDUSG Corporation

ASTM Committee E05

Symposium on Uncertainty in Fire Tests

June 16, 2011 – Anaheim, CA

Today’s Presentation

• Background

– Type X (special fire resistant) gypsum board

– Gypsum Association research program

• Three bench tests

• Correlation of bench tests to ASTM E119 tests

• Bench tests’ precision & bias

– Repeatability & reproducibility

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Type X gypsum board

• ASTM C 1396 – 09a

4.3 Gypsum Board, type X (Special Fire-Resistant):

4.3.1 …provides not less than 1 h fire-resistance rating for boards ⅝ in. thick or ¾ h fire-resistance for boards ½ in. thick applied…on each side of load bearing 2 by 4 wood studs…partition…tested in accordance with Test Methods E119.

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Problems with C1396 definition

• ASTM E119 load bearing wood stud wall– Test apparatus availability

• 10 furnaces in North America

– Expensive• $10k ~ $20k per test

– E119 test variability– Influenced by non-gypsum components

• Unsuitable for plant QA– Cannot provide timely feedback to production

process– Need small scale tests of gypsum board alone

Gypsum Association Research Program, 2003 - 2009

• Product Standard Task Group (PSTG)– Ad hoc task group– Objective:

• Develop improved definition of type X based on specific properties of the gypsum board alone.

• Program– Identify key properties– Develop suitable bench test(s)– Testing & validation

• Bench test round robins• Correlate bench test results to E119

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Fire Protection Membrane Performance Criteria

• Move with the framing

• No large cracks or fall-off

• Reduce heat transfer

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Three Bench Tests

• High-Temperature Core Cohesion– High-temperature strain (movement)– Does sample break upon deflection while exposed to fire?

• High-Temperature Shrinkage– Cracking– In-plane linear shrinkage at 1562°F (850°C)

• High-Temperature Thermal Insulation– Thermal barrier– Time rate of temperature rise at unexposed surface.

• Theory & description– Shipp, P. H., and Yu, Q., “Thermophysical Characterization of Type X Special

Fire Resistant Gypsum Board”, Proceedings of the Fire and Materials 2011 Conference, San Francisco, 31st January – 2nd February 2011, InterscienceCommunications Ltd., London, UK, p417-426.

– ASTM ballot C11 (09-04) item 1

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Correlation to E119*

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35

40

45

50

55

60

65

70

75

80

40 45 50 55 60 65 70 75

Pre

dic

ted

Fir

e R

esis

tan

cen

Ra

tin

g, m

inu

tes

Fire Resistance Rating, minutes

*Shipp & Yu, Fire & Materials Conference , 2011 Proceedings, p417-426.

Bench Tests – Precision & Bias

• Interlaboratory Studies (ILS)– American Gypsum Co. LLC

– CertainTeed Gypsum Inc.

– Georgia-Pacific Gypsum LLC

– Lafarge North America Inc.

– National Gypsum Co.

– PABCO Gypsum

– Temple-Inland

– United States Gypsum Co.

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Uncertainty Analysis

• Bias

– No standard reference material

• Precision

– Repeatability (r)

– Reproducibility (R)

– Coefficient of Variation (CV)

• ASTM E691-09e

– Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method

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High-Temperature Core Cohesion Test

• Simple categorization test– Binary pass/fail result

• ILS– 7 manufacturers

– 4 different type X samples

– 1 manufacturer also tested non-type X gypsum boards (½” & ⅝”)

• Over 400 test specimens evaluated– No “false positive” or “false negative” outcomes

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High-Temperature Shrinkage Test

• 3 shrinkage round robins

– SRR1 & SRR2 = 7 labs

– SRR4 = 6 labs

– Test method progressively refined

• 4 samples per round robin

• 12 replicates per sample

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SRR2 – Sample ‘T’

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Material

T

Laboratory 1 2 3 4 5 6 7 8 9 10 11 12

A 0.043 0.040 0.052 0.053 0.044 0.046 0.041 0.040 0.050 0.053 0.044 0.044

B 0.040 0.037 0.047 0.045 0.043 0.045 0.038 0.036 0.045 0.046 0.045 0.051

C 0.039 0.043 0.042 0.037 0.044 0.044 0.039 0.046 0.044 0.041 0.044 0.043

D 0.040 0.041 0.045 0.044 0.039 0.038 0.037 0.043 0.042 0.041 0.036 0.036

E 0.043 0.047 0.041 0.043 0.044 0.040 0.039 0.048 0.041 0.043 0.047 0.042

F 0.042 0.044 0.046 0.046 0.038 0.038 0.041 0.044 0.045 0.045 0.037 0.038

G 0.042 0.044 0.046 0.046 0.042 0.040 0.043 0.045 0.046 0.044 0.044 0.042

H 0.015 0.012 0.014 0.021 0.022 0.020 0.018 0.018 0.013 0.018 0.013 0.013

h-critical k-critical

2.15 1.49

Laboratory Avg s d h k CV

A 0.046 0.005 0.006 0.669 1.381 10%

B 0.043 0.004 0.004 0.371 1.288 10%

C 0.042 0.003 0.003 0.284 0.782 6%

D 0.040 0.003 0.001 0.076 0.893 8%

E 0.043 0.003 0.004 0.374 0.812 7%

F 0.042 0.004 0.002 0.250 1.015 8%

G 0.044 0.002 0.004 0.416 0.557 4%

H 0.016 0.004 -0.023 -2.440 1.013 21%

Avg of cell avgs, x: 0.040 0.003 = Avg std dev Avg CV: 9%

Std dev of cell avgs, sx: 0.010

Repeatability std dev, sr: 0.003 Repeatability limit, r: 0.010

Reproducibility std dev, sR: 0.010 Reproducibility limit, R: 0.028

Test Results, xi,j

Material

T

Laboratory 1 2 3 4 5 6 7 8 9 10 11 12

A 0.043 0.040 0.052 0.053 0.044 0.046 0.041 0.040 0.050 0.053 0.044 0.044

B 0.040 0.037 0.047 0.045 0.043 0.045 0.038 0.036 0.045 0.046 0.045 0.051

C 0.039 0.043 0.042 0.037 0.044 0.044 0.039 0.046 0.044 0.041 0.044 0.043

D 0.040 0.041 0.045 0.044 0.039 0.038 0.037 0.043 0.042 0.041 0.036 0.036

E 0.043 0.047 0.041 0.043 0.044 0.040 0.039 0.048 0.041 0.043 0.047 0.042

F 0.042 0.044 0.046 0.046 0.038 0.038 0.041 0.044 0.045 0.045 0.037 0.038

G 0.042 0.044 0.046 0.046 0.042 0.040 0.043 0.045 0.046 0.044 0.044 0.042

h-critical k-critical

2.05 1.48

Laboratory Avg s d h k CV

A 0.046 0.005 0.006 0.669 1.381 10%

B 0.043 0.004 0.004 0.371 1.288 10%

C 0.042 0.003 0.003 0.284 0.782 6%

D 0.040 0.003 0.001 0.076 0.893 8%

E 0.043 0.003 0.004 0.374 0.812 7%

F 0.042 0.004 0.002 0.250 1.015 8%

G 0.044 0.002 0.004 0.416 0.557 4%

Avg of cell avgs, x: 0.043 0.003 = Avg std dev Avg CV: 8%

Std dev of cell avgs, sx: 0.002

Repeatability std dev, sr: 0.003 Repeatability limit, r: 0.010

Reproducibility std dev, sR: 0.004 Reproducibility limit, R: 0.010

Test Results, xi,j

SRR2 – Sample ‘T’

• Drop Lab ‘H’

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SRR2

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-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

S S S S S S S S T T T T T T T T WWWWWWWW X X X X X X X X

A B C D E F G H A B C D E F G H A B C D E F G H A B C D E F G H

Between-lab statistic, h

High-temperature shrinkage, RR2

SRR2

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-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

S T W X S T W X S T W X S T W X S T W X S T W X S T W X S T W X

A A A A B B B B C C C C D D D D E E E E F F F F G G G G H H H H

Between-lab statistic, h

High-temperature shrinkage, RR2

SRR2

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0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

S S S S S S S S T T T T T T T T WWWWWWWW X X X X X X X X

A B C D E F G H A B C D E F G H A B C D E F G H A B C D E F G H

Within-lab statistic, k

High-temperature shrinkage, RR2

SRR2

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0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

S T W X S T W X S T W X S T W X S T W X S T W X S T W X S T W X

A A A A B B B B C C C C D D D D E E E E F F F F G G G G H H H H

Within-lab statistic, k

High-temperature shrinkage, RR2

High-Temperature Thermal Insulation

• 4 thermal insulation round robins

– 5 to 7 labs

– Test method progressively refined

• 4 samples per round robin

• 4 replicates per sample

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Shrinkage & Thermal Insulation ILS Summaries

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ILS

No. of

Labs,

p

Materials

Average,

x avg

Repeatability

Std Dev,

s r

Reproducibility

Std Dev

s R

Repeatability

Limit,

r

Reproducibility

Limit,

R

Coefficient

of Variation,

CVavg

SRR1 7 S, T, W, X 0.050 0.0046 0.0062 0.0129 0.0172 9%SRR2 7 S, T, W, X 0.047 0.0038 0.0050 0.0108 0.0141 8%SRR4 6 R, U, V, Z 0.064 0.0044 0.0051 0.0124 0.0143 7%

TI1 7 S, T, W, X 51.4 1.62 3.75 4.55 10.49 3%TI2 6 S, T, W, X 54.7 3.88 5.77 10.87 16.17 5%TI4 5 R, U, V, Z 49.3 1.89 3.36 5.29 9.41 3%TI5 6 P50 17.7 0.18 0.92 0.50 2.58 1%TI5 5 P60 26.3 0.30 0.72 0.83 2.01 1%TI5 6 P64 27.9 0.54 0.72 1.50 2.03 2%TI5 6 P75 31.7 0.63 1.57 1.77 4.41 2%

High-Temperature Shrinkage

High-Temperature Thermal Insulation

Conclusions

• Core cohesion test very consistent.

• r&R determined for the high-temperature shrinkage & thermal insulation tests.

• All three test methods are practical for use in a plant quality assurance program.

• The largest source of uncertainty in predicting gypsum board performance in the ASTM E119 test was the E119 test itself, not the variability of the bench tests.

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