U-value for steel door?

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Author Message David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1194 Registered: 03-2002 Posted on Thursday, May 19, 2011 - 04:16 pm:    What is the U-value for a steel door/frame with either polystyrene or polyurethane core? I can't seem to find this information on manufacturer's websites. Ellis C. Whitby, PE, CSI, AIA, LEED® AP Senior Member Username: ecwhitby Post Number: 103 Registered: 03-2003 Posted on Thursday, May 19, 2011 - 04:29 pm:    Which manufacturers did you check? These have values: http://www.cecodoor.com/default.aspx?Doc=products/polydrs.htm http://www.steelcraft.com/app_sol_art_03_coreofhollowmetaldoors.asp George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 597 Registered: 11-2004 Posted on Thursday, May 19, 2011 - 04:30 pm:    I have that in our Steelcraft Technical Manual. It varies depending on configuration of the door from 0.48 to 0.69 according to SDI 113-01 thermal performance tests. Send me your email address to geverdin@irco.com and I'll send you the page from the manual, or the whole manual if you need it. George A. Everding AIA CSI CCS CCCA Ingersoll Rand Security Technologies St. Louis, MO George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 598 Registered: 11-2004 Posted on Thursday, May 19, 2011 - 04:43 pm:    Note that there is a dramatic difference between calculated thermal values (by ASTM C 518) and tested thermal values (by ASTM C 1363). The websites posted above give calculated values - the values I listed are tested values. There are also significant differences between the old ASTM C236-89(93) “Standard Test Method for Steady-State Thermal Performance of Building Assemblies by Means of a Guarded Hot Box” and the current standard, ASTM C1363-05 “Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus”. As mentioned, SDI 113 requires tested values by C1363. George A. Everding AIA CSI CCS CCCA Ingersoll Rand Security Technologies St. Louis, MO David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1195 Registered: 03-2002 Posted on Friday, May 20, 2011 - 01:22 pm:    George, "Dramatic difference" is an understatement! Some of the tested thermal values have been reduced by 1/3 to 1/4 from the calculated values. I get really suspicious when a door manufacturer claims to get R11 in an all steel door when the polyurethane core is only R6 per inch! George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 599 Registered: 11-2004 Posted on Friday, May 20, 2011 - 01:57 pm:    I see that both we and our competition make the same statement about r11. Calculated value is just a typical one square foot cross section and ignores things like thermal bridging and so forth - it's like the calculated value of a stud wall which traditionally ignored the studs. If you are only considering the faces and insulation, it calculates pretty impressive values. That's why SDI requires testing the actual assembly: a 3' x 7' door or 6' x 7' pair, fully operable, with frame and hardware. Similar to this is STC ratings - they are always better when calculated than they are when tested. George A. Everding AIA CSI CCS CCCA Ingersoll Rand Security Technologies St. Louis, MO John Regener, AIA, CCS, CCCA, CSI, SCIP Senior Member Username: john_regener Post Number: 534 Registered: 04-2002 Posted on Friday, May 20, 2011 - 05:31 pm:    George: Does it matter whether the door is open or closed <g>? David Axt, AIA, CCS, CSI Senior Member Username: david_axt Post Number: 1196 Registered: 03-2002 Posted on Friday, May 20, 2011 - 05:53 pm:    At about R2....it does not really matter much, though air infiltration is increased. ;-) George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 600 Registered: 11-2004 Posted on Friday, May 20, 2011 - 07:09 pm:    Most days in St. Louis it matters... but not today - perfect weather and a wee bit too early for the flies and skeeters - doors and windows are wide open (until the rain starts). George A. Everding AIA CSI CCS CCCA Ingersoll Rand Security Technologies St. Louis, MO David Stutzman Senior Member Username: david_stutzman Post Number: 72 Registered: 07-2002 Posted on Friday, May 20, 2011 - 07:13 pm:    According to SDI 113-01 (R06) found on SDI's website, the test for steel doors is not ASTM C1363, but rather ASTM C1199. ASTM C1199 relies on test method ASTM C1363. Doors are tested as an opening with the frame, hardware and weatherstrip, not just as a door. The standard does not address how the frame is installed during the test: whether filled with insulation or mortar or left unfilled. SDI 113 assigns specific surface temperatures for the interior and exterior door faces T1 = 70 deg F for interior (warm) and T11 = 0 deg F for exterior (cold). ASTM C1199 and C1363 both use the symbol T2 for the exterior surface temperature. This allows tested door thermal performance to be compared between manufacturers. Since the test result is reported for an entire assembly, it may be important to ask for a description of the tested assembly since it appears the frame construction and installation may be at the manufacturer's discretion. The test measures U-value in the absence of solar and air leakage effects. So perhaps you could still claim R2.1 even if the door is open. George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 601 Registered: 11-2004 Posted on Friday, May 20, 2011 - 07:49 pm:    Yes, thank you. I pulled the C1363 reference from Steelcraft's data, which was referring to the replacement of C236 with C1363. I'll send you the pages from the tech data. Current SDI 113 is as you stated. George A. Everding AIA CSI CCS CCCA Ingersoll Rand Security Technologies St. Louis, MO