ASTM E 119 test accuracy

OK. Noone has taken a shot at this in acouple of days. I'll try to at least better understand the question.

Non expert attempt at understanding the question. You state thatthe concrete moisture content is 95%

I was under the impression that the chemically bonded proportion of water was 25%; the physically bonded water content was an additional 20% total 45%.Water loss from evaporation probably another ~10%??

Not sure where you are getting the 95-98% figure from.

BTW, I do not have copy of E119 so I'm just trying to get oriented to your question at this time.

milo

To clarify the question, light weight concrete was poured over metal decking as a mock up of an actual construction salb and within 15 days , they tested the moisture content to be at 95 to 98% . With this , ASTM E 119 test was performed. The objective to this test is to monitor transfer of heat thru the concrete slab. So my take on this , is that heat transfer can not be accurately measured because of the high moisture content. Seems like when they fired up the concrete slab , vaporization occurs, extensively I should say.So is it fair and accurate to say that the accuracy of the test is in question ?

The test method described in the ASTM E 119 standard evaluates (in terms of endurance time) "the ability of an assembly[/system] to contain a fire or to retain its structural integrity, or both, during the test conditions imposed by the standard." By the standard's own definition, ASTM E 119 does not assess individual materials or products for their fire-resistance characteristics. ASTM E 119 does, however, generate results that can be used to evaluate the general fire resistance of assemblies/systems made up of multiple components, such as walls, columns, slabs, and floor- and roof-ceiling systems under laboratory conditions.

I think that your read of it being to "as I understand, is to monitor heat transfer on the exposed side of the specimen undergoing a fire test ie: a concrete slab for its fire rating." Is not what the test is really trying to determine.

Its trying to establish "the ability of an assembly[/system] to contain a fire or to retain its structural integrity, or both, during the test conditions imposed by the standard."

My take would be does the test on the slab your company prepared and aged prior to test reflect the performance of the slab in actual conditions say five or ten years down the road. The test does n't really care iof the concrete sheds moisture, it wants to determine the integrity of the materials and their ability to resist fire, as they are deployed in the construction.

That's how I think the protocol and your test should be thought about.

Here is some more info about the use of ASTM E 119 from Georgia PAcific's website:

Model building codes reference the ASTM E 119 standard test method (or one of its closely allied counterparts.) Gypsum board systems are tested based on the requirements of the ASTM E 119 standard. Referencing the same test method(s) by the building codes facilitates the descriptions and comparisons of fire resistance ratings of assemblies/systems that have been objectively evaluated. Numerical fire resistance ratings created by ASTM E 119 tests may be considered as benchmarks for comparison purposes. The higher the numerical rating (i.e., one, two, three, or four hour(s)), the longer the assembly's/system's comparative endurance. The hourly fire resistance ratings found in commercial and residential building codes that refer to an ASTM E 119 test do not imply that a specific assembly/system will remain intact for the prescribed time of the hourly rating in an actual fire situation.

Fire resistance classifications are based on results of tests conducted on assemblies/systems created with specific materials and built in a specified manner; therefore, variations from the test conditions or the construction specifications (including, but not limited to, the type and size of materials and the method of construction) will affect the results of fire tests. Because fire exposure conditions vary with changes in a wide variety of factors, including the amount, nature, and distribution of available fuel; ventilation; and the size, configuration, and other characteristics of the compartment, the test method contained in the ASTM E 119 standard should not be considered to be representative of all fire conditions. Fire resistance ratings created through use of the ASTM E 119 test method reflect a relative measure of comparative assembly's/system's performance under specific fire test conditions. ASTM E 119 test results should not be construed as having determined performance of an assembly/system under different conditions.

http://www.gp.com/build/PageViewer.aspx?repository=bp&elementid=3487

The NIST has a powerpoint about their testing of WTC floor panels for their investigation here:

http://www.nist.gov/public_affairs/Project%206%20E119%20Presentation%208-28-03.pdf

See especially slides 6 and 13.

milo

Milo

I understand where your coming from , reading the summary of ASTM E 119 , it seems like there are more questions than answers . Case and point, Condition of test specimen shall not be conducted until final strength is achieved. In our case the concrete is like 15 days old and do you think this is accceptable and be subjected to the test ? 2nd point, test is to determine the ability of an assembly to contain a fire and its structural integrity. Well when we do the test, the concrete slab is subjected to fire and therefore heat is created. Of course concrete won't burn , worst case is for the steel to deflect. Now maybe this is a structural test and not a fire test. Should we have use a different test method ? to determine the hourly rating ? 3rd point, this test is supposed to measure transmission of heat, yes the fact that fire can not penetrate thru the concrete slab then heat shall be measured on the exposed side , correct ? If you agree , then how accurate can it be when ur moisture content is so high ? vaporization takes place . , right ? so technically no heat transfer can be measured correctly , which comes down to , did the structure hold up after being subjected to this 1 hr test . hhmm so we are back to square one. this could just be a structural test then. TO BE CONT>

this could just be a structural test then???

YEP: "evaluate the general fire resistance of assemblies/systems made up of multiple components, such as walls, columns, slabs, and floor- and roof-ceiling systems under laboratory conditions."

milo "Good to be back"