b'Polyisocyanurate InsulationAn Analysis in ProgressBy Sudhakar Molleti, Bas Baskaran National Research Council Canada is evaluatingand Dominique Lefebvreaged in-service polyisocyanurate insulationFishburn Sheridan & Associates Ltd., Kanata, Ontario; Dean-Chandler Roofing Ltd., Scarborough, Ontario; and Daniel Theriault Roof Inspection, Edmundston, New Brunswick, collected and provided the insulation samples. Helen Yew and David Van Reenen, NRC technical officers, assisted in conducting the experiments.C ommercialroofsystemsPolyisocyanurate is the predomi- LTTR accelerategas represent vast surface areasnantinsulationmaterialusedinTo determine thermal drift, the of building envelopes, andcommercial roof systems in Northconcept of long-term thermal re- diffusion,result-the rate of energy transfer acrossAmerica. It has a higher R-value persistance (LTTR) was introduced ining in a reduction of these roofs influences buildingsthickness compared with other com- the 1990s through research con- thermal resistance that rep-holisticenergyperformance.mon insulation materials. Polyisocy- ductedbyOakRidgeNationalresents insulations aging process.roofing contractors to deter-Thermalinsulationaffectsthisanurateisaclosed-cellinsulationLaboratory, Oak Ridge, Tenn., inLTTR represents a 15-year, time- mine the actual thickness of energy transfer and obtaining ac- materialthatcontainsablowingcooperation with NRCA, PIMAweightedaverageoftheinsula- the insulation required to meet curatethermalresistancevaluesagent within its cells to reduce theand the Society of the Plastics In- tions R-value, derived from fivebuilding codes and estimate the (R-values) for insulation productsrate of heat transfer. Similar to otherdustry. Standards have been de- years of relative aging. It is notedlong-term energy performance of a is essential for specifying heatingblown insulating foams, the blowingveloped to measure LTTR usingthis accelerated aging method oc- roof assembly. However, minimal and cooling loads, HVAC equip- agent diffuses over time, resulting inan accelerated aging slicing andcurs under laboratory conditions. studieshavevalidatedlaboratory ment and the long-term energya change in R-value. This change inscaling method, where thin slicesKnowing the LTTR of insulationmethods by investigating in-service use of building envelopes.R-value is known as thermal drift. offoamspecimensareusedtoenables roof system designers andaging of insulation. Some studies Figure 1RECEIVED SAMPLE ID TESTED SAMPLE # YEAR OF INSTALLATION CITY OCCUPANCY ASHRAE/NBCC CLIMATIC ZONE1 1 1998 Ottawa, ON Offices & Laboratories 62 2 2003 North Bay, ON Offices & Workshops 73 3 2006 Inverary, ON Sensitive Equipment 64 4 1999 Ottawa, ON Offices & Laboratories 65 5 Unknown Ottawa, ON School 66 6 2000 Gatineau, QC Cinema 67 7 Unknown Strathroy, ON Offices 58 8 Unknown North Bay, ON Offices 79 9 1991 Kingston, ON School 610 Not Tested 1997 Kingston, ON School 611 10 1988 Toronto, ON Stadium 512 11 1992 Sydenham, ON School 713 Not Tested 2000 Bristol, NB School 614 Not Tested 2000 Saint-Joseph-de-Madawaska, NB School 715 Not Tested 2000 Caraquet, NB School 616 Not Tested 2000 Keswick, NB School 6Figure 1: Year of installation, city, occupancy and ASHRAE climatic zone of polyisocyanurate insulation samples collectedORN THE ONLY SOURCE FOR PROFESSIONAL ICI ROOFING CONTRACTORS IN ONTARIO ONTARIO ROOFING NEWSISSUE 1 20209'