Subject: NRCA MRCA Joint Technical Bulletin. Date: January 2008 NOT COMPROMISE.

Transcription

1 Roofing No NRCA MRCA Joint Technical Bulletin Attached is a copy of the NRCA/MRCA Joint Technical Bulletin which was presented at the 1987 MRCA Convention. This document is entitled, In-Service R-Values (ISR) for Polyisocyanurate and Polyurethane Roof Insulation Boards, dated November, Please note that the document recommends that designers, users and other affected parties use an R-Value of 5.6 per inch of foam thickness as a reasonable guide when calculating thermal resistance of polyisocyanurate and polyurethane insulation boards. products are manufactured

2 Roofing No Roof Spanability The minimum thickness of Roof Insulation required to span metal deck flutes, can be determined by multiplying the flute span distance by the constant multiplier of the to be used. The formula assumes normally occurring roof traffic and proper staging during installation of the roofing system. Type Constant (Multiplier) I 1.25 VIII 1.15 II 1.05 IX 0.95 Example A metal deck has a flute span of 1-7/8, the necessary thickness of Type I EPS would be: EPS Type Flute Span Multiplier = EPS Thickness I 1-7/8 X 1.25 = 2.3 This formula is for EPS alone. When approved coverboards are used, the minimum thickness of the EPS can be 1 for all densities, when metal deck flute spans are less than 3. This formula is used for normal occurring metal roof deck situations where EPS thicknesses of 3 or less are required. Some minor deformation may occur in heavy traffic areas. If special requirements need to be met, please contact your local Suppilier before installation. products are manufactured

3 Roofing No Low Temperature R-Values The following chart has been assembled to aid in the design of applications in low temperature conditions. All values are design R-Values per one inch of thickness. Typical Design R-Values* for Temperatures Belows 40 0 F (4.40 C) Type I VIII II IX Temperature: 40 0 F (4.4 0 C) F ( C) F ( C) F ( C) products are manufactured

4 Roofing No Long Term R-Value of Polyisocyanurate Insulation There has been extensive debate regarding the long-term or In-Service R-Value of polyisocyanurate insulations. Numerous scientific studies have been conducted by scientists, researchers, and professional associations attempting to determine the actual performance of polyisocyanurate insulation when applied as roof, wall and other insulation applications. The central issue is whether polyisocyanurate retains its R-Value over its useful life. It is argued by many that polyisocyanurate loses R-Value due to loss of its low conductance blowing agents early in its life, while continuing to lose R-Value as normal atmosphere infiltrates its cell structure. Many organizations have come out with published recommendations that polyisocyanurate does in fact lose R-Value, and if used it should be designed with the long term R-Value. Foam-Control has had occasion to test samples of polyisocyanurate taken from an 8 year old roof from the Northwestern part of the United States. The insulation was used under a light colored single ply roofing membrane. Nominal 4 samples were submitted to an independent laboratory for R-Value Testing under AS Standard C518-91, Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus. The polyisocyanurate samples were in excellent condition. They were dry and contained relatively no moisture. The density of the samples exceeded 2.5 lbs. per cubic foot and were faced with felt paper on both sides. The tests confirmed that polyisocyanurate insulation* does undergo thermal drift and does indeed lose significant R- Value. One sample tested at 5.48 R-Value per inch, the second tested at 5.26 R-Value per inch, having an average of 75 o F per inch. The total R-Value for the samples (actual average thickness measured 3.8 ) averaged Reminder: Foam-Control molded expanded polystyrene (EPS) does not experience thermal drift and subsequent R- Value loss. EPS has a stable R-Value due to its processing technique which captures normal atmosphere within its cell structure, thereby making for stable R-Values within the EPS material. Update: The same samples were resubmitted to an independent laboratory for further R-Value analysis when the samples were ten years old. The samples tested in December of 1994 had an average R-Value of 5.37 per inch. Testing of the same samples after 10 years average an R-Value of Thermal loss was still occurring. products are manufactured

5 Roofing No R-Value and Long Term R-Value Background The blowing agents used in extruded polystyrene, polyisocyanurate, and polyurethane foams provide for an initial high R-value. During the life of the foam, air from the atmosphere diffuses into the cells of the foam and reduces the R-value. In addition, the blowing agents themselves diffuse out of the foam, further reducing the R-value. Test methods have been developed to help provide information and standardize the reporting of R-value for materials with blowing agents other than air. The following test methods have been developed: AS C Standard Test Method for Estimating the Long-Term Change in the Thermal Resistance of Unfaced Rigid Closed-Cell Plastic Foams by Slicing and Scaling under Controlled Laboratory Conditions. ISO Ageing of Thermal Insulation Materials Determination of the Long-Term Change in Thermal Resistance of Closed-Cell Plastics (Accelerated Laboratory Test Methods). CAN/ULC-S Determination of Long-Term Thermal Resistance of Closed-Cell Thermal Insulating Foams. All three test methods provide a similar method to estimate the Long Term Thermal Resistance (LTTR) or long term R-value of insulations. Diffusion theory for gases demonstrates that the diffusion of gases in foam is mathematically dependent upon the thickness. Each of the methods involves cutting thin sections approximately 10 mm (3/8 ) from a sample of thicker insulation such as 100 mm (4 ). Due to the relative size of the thin samples, diffusion of air into the foam and blowing agents out of the foam is quicker than for the original thick sample. Each test method provides a LTTR or long term R-value. However, these LTTR s can not be compared directly. For example, the AS standard is very general is scope and does not state the time at which the LTTR should be reported. The AS standard also provides for a time weighted average of the R-value. This is an average R-value for the insulation over the time period considered. The AS C1303 is very broad and has not been promoted by manufacturers of foam insulation with blowing agents. The AS C1303 standard can be used to estimate the R-value for insulation over long periods of time, such as 5,10,15,20, or 25 years. The ULC/CAN standard is based upon AS C1303 and provides a LTTR, long term R-value, estimate for the material after 5 years storage. This test standard is being recognized as a basis for comparison between foam insulation with blowing agents. The advantage is that the testing can be completed in relatively short times. The CAN/ULC-S-770 standard DOES NOT provide for a long term R-value, such as after 10, 15, 20, or 25 years. The ISO is very broad and is conducted in a similar manner to the AS C1303. Of particular interest, ISO has a method similar to the CAN/ULC standard but provides for an estimate of the long term R-value after 25 years. The ISO standard DOES provide for the determination of a long term R-value. Recommedations for all insulation users: 1. Ask for AS C1303 estimate of the R-value after 25 years. 2. Only use CAN/ULC S-770 for comparison among similar foams. 3. Ask for the ISO estimate of the R-value after 25 years. 4. The R-value for expanded polystyrene (EPS) insulation does not change with age. To make a proper insulation selection, be sure to only compare the R-values for EPS to the R-value after 25 years for foam insulations with blowing agents determined from testing in accordance with AS C1303 or ISO products are manufactured

6 Roofing No R-Value and Long Term R-Value Polyisocyanurate Insulation Manufacturers of Polyisocyanurate insulation are promoting the use of the long term R-value techniques in AS C1303 and CAN/ULC S770. The Polyisocyanurate Insulation Manufacturers Association, PIMA, is promoting using some form of time weighted average over 15 years 1. Their literature states that using techniques in AS C1303, CAN/ULC S770 provides the following long term R-values for some Polyisocyanurate insulations. The R-value published by polyisocyanurate insulation manufacturers is ONLY for 5 years. The long term R-value for polyisocyanurate insulations is LOWER than that represented by the PIMA published information. 1 Refer to Polyiso Performs - PIMA (Polyisocryanurate Insulation Manufactureres Association) Average LTTR Values for Polyiso with Hydrocarbon Blowing Agents 1 POLYISO LTTR THICKNESS R-VALUE (inches) The exact variations from the standard test methods are not described. As is well known, deviations from standard test methods make the results unreliable for comparison. Although this is a step forward for the Polyisocyanurate insulation industry to recognize that estimates of long term R-value, the use of their modified test method only allows for Polyisocyanurate insulation manufacturers to compare performance among Polyisocyanurate insulations. The use of the modified PIMA method DOES NOT provide for determination of a long term R-value, such as after 10, 15, 20, or 25 years. The PIMA method only provides for the determination of the R-value after 5 years. products are manufactured

7 Roofing No Use of Direct to Deck Application & UL Construction 458 Architects, building owners, roofing contractors, and building officials often ask whether Expanded Polystyrene (EPS) insulation can be applied directly to a fluted metal deck without a thermal barrier and be in compliance with the building code. The answer is YES. This bulletin helps explain the recognition of installed directly to a metal deck as part of a UL fire classified roof deck construction. The requirements f or thermal barrier application with foam plastics is covered by the 2003 International Building Code (IBC). IBC Section requires that foam plastic shall be separated from the interior of a building by an approved thermal barrier unless approved for in sections or Thus, most installations of foam plastics in building construction require a thermal barrier. However, the code recognizes that roof deck constructions may not require a thermal barrier when evaluated under recognized test methods. The code recognized application of foam plastics in roofing without a thermal barrier is covered specifically by section of the IBC. This section states: A thermal barrier is not required for foam plastic insulation that is part of a Class A,B, or C roof-covering assembly, provided the assembly with the foam plastic insulation satisfactorly passes FM4450 or UL1256. Underwriters Laboratories (UL), a leader in the investigation of fire safety issue, has investigated the performance of EPS insulation in accordance with UL1256 as required by the building code. As evidence of compliance with UL1256, UL publishes fire classified roof constructions to educate users on suitable roof deck constructions. UL published roof deck Construction no. 458 as a fire resistant assembly in compliance with UL1256. This listing is shown on page 2. As a requirement of Construction 458, the insulation must comply with UL listings for BRYX or TGFU. Foam-Control EPS is manufactured under UL file R11812 with compliance to BRYX and TGFU. Thus, is a suitable roof insulation for use in UL Construction 458. Summary 1. Use of foam plastic insulation in a roof assembly without a thermal barrier must comply with the building code by meeting section of the IBC 2. Section of the IBC requires that the assembly be evaluated by FM4550 or UL UL has investigated EPS insulation as part of an assembly in accordance with UL UL published fire classified roof deck Construction 458 as a result of these investigations. 5. Foam plastic insulation used in UL Construction 458 must conform to UL listings for BRYX or TGFU. 6. insulation is listed by UL File R11812 as a BRYX and TGFU compliant material. 7. insulation is suitable for direct to metal deck application when installed in conformance with UL Construction 458. products are manufactured

8 Page Bottom TGKX.458 Roof Deck Constructions Design/System/Construction/Assembly Usage Disclaimer Authorities Having Jurisdiction should be consulted in all cases as to the particular requirements covering the installation and use of UL Listed or Classified products, equipment, system, devices, and materials. Authorities Having Jurisdiction should be consulted before construction. Fire resistance assemblies and products are developed by the design submitter and have been investigated by UL for compliance with applicable requirements. The published information cannot always address every construction nuance encountered in the field. When field issues arise, it is recommended the first contact for assistance be the technical service staff provided by the product manufacturer noted for the design. Users of fire resistance assemblies are advised to consult the general Guide Information for each product category and each group of assemblies. The Guide Information includes specifics concerning alternate materials and alternate methods of construction. Only products which bear UL's Mark are considered as Classified, Listed, or Recognized. Roof Deck Constructions See General Information for Roof Deck Constructions Construction No. 458 June 19, 2008 Uplift-Not Investigated Fire-Classified 1. Supports Structural steel or other materials acceptable to authorities having jurisdiction. 2. Steel Deck No. 22 MSG min, 1-1/2 in. deep unperforated coated steel, fluted on 6 in. centers. Welded or mechanically fastened to supports in accordance with deck manufacturer's recommendations. 3. Rigid polystyrene insulation, EPS, loose laid or mechanically fastened in one or more layers, Classified by Underwriters Laboratories Inc, under the Roof Deck Construction Category "Foamed Plastic" as an alternate, to any Classified polystyrene foamed plastic insulation board (EPS) can be used. See Foamed Plastic (BRYX) category in the Building Materials Directory or (TGFU) category in the Roofing Materials and Systems Directory. Total thickness and density of insulation not to exceed an equivalent of 10 in. at 1 PCF density. Example: an equivalent combination would be 8 in. at a 1.25 PCF density.

9 Or insulations which are Classified by Und. Lab. (Roofing Materials and Systems Directory, Roof Deck Construction, Building Units) for the following manufacturers: ATLAS ROOFING CORP (View Classification) "Vented R CrossVent" 3A. In lieu of Item 3, Rigid Foamed Plastic With Vented Roof Deck* Vented Nail-base roof deck products which are Classified by UL - Roofing Materials and Systems Directory, Roof Deck Construction, Building Units (TIAR)) intended to provide ventilation between the nailed decking and a foamed plastic insulated steel deck construction. The nail-base deck consists of 7/16-in. thick (min) oriented strand board (OSB) or 15/32-in. thick (min) plywood. ATLAS ROOFING CORP "Vented-R" or "CrossVent" 4. Barrier Board* (Optional) A min 3/4 in. perlite, 1/2 in. wood fiber, 1/2 in. gypsum board or G-P Gypsum 1/4 in. DensDeck cover board or min. 1/4 in. Owens Corning Specialty & Foam Products "Strataguard" or minimum 1/4 in. thick United States Gypsum Co. "SECUROCK " Roof Board (Type FRX-G) placed over the insulation. Required when a single ply membrane is mechanically fastened or fully adhered. 5. Fasteners (Optional) Fasteners used to attach foamed plastic and cover board to steel deck. Fasteners are selfdrilling, self-tapping roof insulation screws with insulation plates. 6. Roof Covering* A max 0.08 in. thick loose laid (ballasted), mechanically fastened or adhered membrane roof covering Classified by Underwriters Laboratories Inc. as Membrane for Roofing Systems (TGFU) as described in the Roofing Materials and Systems Directory. 6A. Metal Roof Deck Panels* (Not shown) In addition to or in lieu of Item 6, the roof covering may consist of a mechanically fastened metal roof deck panel assembly. See Metal Roof Deck Panels (TJPV) as described in the Roofing Materials and Systems Directory. 6B. Roof Covering* In lieu of Item 6, a modified bitumen membrane roof covering over Barrier Board (Item 4) Classified as Membrane for Roofing Systems (TGFU). Foamed Plastic insulation (Item 3) limited to 6 in. thickness. 6C. Roof Covering** I n lieu of Item 6 and in combination with Item 3A; asphalt shingles, fiber-cement tile and metal (or wood) shingles or shakes; an underlayment (optional) and/or vapor barrier (optional) Classified as Prepared Roofing Accessories (TGDY). Roof covering to be installed as specified by manufacturer. *Bearing the UL Classification Mark Last Updated on Questions? Notice of Disclaimer Page Top Copyright 2008 Underwriters Laboratories Inc. The appearance of a company's name or product in this database does not in itself assure that products so identified have been manufactured under UL's Follow-Up Service. Only those products bearing the UL Mark should be considered to be Listed and covered under UL's Follow-Up Service. Always look for the Mark on the product. UL permits the reproduction of the material contained in the Online Certification Directory subject to the following conditions: 1. The Guide Information, Designs and/or Listings (files) must be presented in their entirety and in a non-misleading manner, without any manipulation of the data (or drawings). 2. The statement "Reprinted from the Online Certifications Directory with permission from Underwriters Laboratories Inc." must appear adjacent to the extracted material. In addition, the reprinted material must include a copyright notice in the following format: "Copyright 2008 Underwriters Laboratories Inc. "

10 Roofing No R-Value for Polyisocyanurate Insulation at 5 Years August 2008 The blowing agents used in polyisocyanurate foams provide for an initial high R-value. During the life of the foam, air from the atmosphere diffuses into the cells of the foam and reduces the R-value. In addition, the blowing agents themselves diffuse out of the foam, further reducing the R-value. Manufacturers of polyisocyanurate insulation promote the use of the long term R-value techniques in AS C1303 and CAN/ULC S770. The AS C1303 and ULC/CAN S770 standards provides a long term thermal resistance (LTTR) or R-value estimate for the material after 5 years storage or a time-weighted average over 15 years. Literature published by PIMA suggests that 2 polyisocyanurate insulation will have an LTTR of 6.05/inch. This independent testing has confirmed that even after only 5 years, the R-value for polyisocyanurate insulation is below the published LTTR or estimated long term thermal resistance. Architects, specifiers, and building owners should ask their insulation manufacturers for R-values over the life of the building. In addition, R-value warranties should be examined closely to see if 100% of the R-value is warranted. Unlike other insulations which lose R-value over time and may have limited warranty coverage, is warranted for 100% of the R-value for 20 years. Independent testing has been conducted on 2 thick polyisocyanurate insulation that was purchased in May, At the time of purchase the R-value was 6.4/inch. The samples were subsequently stored under laboratory conditions of 72 0 F and 50% humidity. After 1 year, the R-value was 6.1/inch. After 5 years, the R-value was 5.5/inch or it has lost almost 15% of its R-value. As the polyisocyanurate insulation continues to age and off gas blowing agents the R-value will continue to drop. R-Values for Polyisocyanurate Insulation Age R-Value/In. Purchase months year year 5.5 products are manufactured trademarks of AFM Corporation, Burnsville,