Plexiglas is a trade name. You can have various materials that are transparent
plastic, but non-the-less they are still plastics. Some will have an auto
ignition temp. and some will not sustain combustion unless directly exposed to
flame. Remove the flame and the product no longer burns. So you might want to
get some specific information on the material. Plexiglas is an acrylic
polymer, with a auto ignition temp of usually 730-750 degrees. You meant NFPA
259, here is the section dealing with plastics.
Table C.1 Potential Heat of Selected Building Materials NFPA 259 Standard Test
Method for Potential Heat of Building Materials 2008
Material Thickness(in.) Density(lb/ft3)
Potential Heat,Weight Basis(Btu/lb)
2. Plastics
a. Polystyrene, wall tile 0.075 65.4
17,420
b. Rigid, polyvinyl chloride, 0.147 86.0
9,290
retardant treated
c. Phenolic laminate 0.063 76.4
7,740
d. Polycarbonate resin 1⁄4 78.7
13,330
In comparison to a non-combustible material, Painted Gypsum Board's values
were, for 1/2", Density=51.2 and Potential Heat 650 Btu/Lb, this was worse case
for gypsum board.
Hope that helps.
Craig L. Prahl, CET
Fire Protection Group
Mechanical Department
CH2MHILL
Lockwood Greene
1500 International Drive
PO Box 491, Spartanburg, SC 29304-0491
Direct - 864.599.4102
Fax - 864.599.8439
[EMAIL PROTECTED]
http://www.lg.com
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of A.P.Silva
Sent: Thursday, November 29, 2007 12:32 PM
To: [email protected]
Subject: RE: Draft stops
My question still remains. Is plexiglass combustible, limited combustible or
non-combustible? Or confirm industry practice? Can someone please help? NFPA
13 refers to NFPA 359 for heat values of material, but I don't have access to
it.
Roland's reply creates another question. My understanding of the purpose of a
draftstop was that it is used to arrest the plume to activate the sprinkler
heads. If they are to be not required when using QR sprinklers, shouldn't the
restriction for deflector to ceiling distance also be removed, or at least
increased. The removal of draftstops must be based on tests for the sensivity
of QR heads. Won't the same tests be applicable for revising deflector to
ceiling distance for QR heads?
Tony
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Roland Huggins
Sent: November 28, 2007 3:28 PM
To: [email protected]
Subject: Re: Draft stops
As a little related information. The requirement for the draft stop almost
disappeared last cycle based on the use of a QR sprinkler. It was approved by
the INstallation TC but the TCC returned it to 13 simply to maintain
correlation with the Building Codes which added it in the past to comply with
13 (currently a catch 22). A proposal to the codes to delete it was SUPPOSE to
have been generated so we could then remove it from 13.
Roland
On Nov 28, 2007, at 1:50 PM, A.P.Silva wrote:
> Draft stops used at floor opening are required to be of non-
> combustible or limited combustible (as per NFPA). I see often
> plexiglass been used for this application. I can't see it being
> classified as non-combustible.
> Would it be
> limited combustible? Or combustible, but industry practice?
>
> Tony
>
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] On Behalf Of Chris
> Payne
> Sent: November 28, 2007 2:06 PM
> To: [email protected]
> Subject: AutoCad LT
>
>> From the Autodesk website:
> Re: what does the LT stands for?
> Officially, it doesn't "stand for" anything. LT is simply Autodesk's
> designation for this scaled-down version of AutoCAD. Differences?
> Other than
> the $3000 difference in price, what you'll find missing are many of
> the customization options (LISP, ARX, VBA), modeling with 3D solids,
> and a number of other features.
>
> Try Softplan.com this is a Residential design package.
>
> Chris Payne
>
> Chris Payne
> Fire Protection Services
>
>
>
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