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The Laboratory Accreditation Program (LAP)

Testing Laboratories
Simulation Laboratories
Individual NFRC Certified Simulators

Products that are labeled with the NFRC Temporary and Permanent Label, or products that are listed on an NFRC Label Certificate in accordance with NFRC requirements, are considered to be NFRC Certified. LAP icon It is through our independent, accredited simulation and testing laboratories that the fenestration manufacturers contract with to obtain their certification for rated values of U-factor, Solar Heat Gain Coefficient, Visible Transmittance, Condensation Resistance, and Air Leakage.

NFRC accredited laboratories undergo extensive auditing procedures to ensure confidence that the laboratories' produce credible and accurate results and without bias.


Simulation laboratories employ NFRC certified simulators that generate the computer simulated results for the fenestration manufacturers.  Certified simulators, as part of the LAP, attend a four-day certification workshop and must pass examinations before they achieve the status of NFRC Certified Simulator.  The NFRC conducts the rigorous certification workshop annually and we have many that attend every year, including simulators that are not affiliated with an NFRC accredited simulation laboratory.  Those NFRC certified simulators not affiliated with an NFRC accredited laboratory are listed on our website and they must maintain their certification every year.  Maintenance of the simulation certification requires participation in an annual Interlaboratory comparison and attendance to mandatory training workshops.

Testing laboratories, those that physically test fenestration products, are an integral part of the fenestration product certification.  The thermal transmittance (U-factor) laboratories are contracted by the fenestration manufacturer to validate their product line.  Validation is achieved by comparing the physical U-factor test (NFRC 102) to the same simulated option.  If they are in tolerance, the entire product line of simulated results are "validated."   When products cannot be simulated, the NFRC has accreditation procedures to for laboratories to physically test for solar heat gain via NFRC 201, visible transmittance via NFRC 202 and NFRC 203, and air leakage via NFRC 400.

The Accreditation Policy Committee (APC) oversees NFRC’s Laboratory Accreditation Program (LAP) and they grant final approval of accreditation of testing and simulation laboratories.