Draft Proposal CB-6 

This concept has been developed by the DOE Building Energy Codes Program (BECP) as a possible code

change proposal to the Commercial provisions of the 2012 International Energy Conservation Code

(IECC).   Interested parties are asked to submit any and all comments on DOE's initial concepts and draft

code change proposals. For instructions on submitting comments, visit:

www.energycodes.gov/development/commercial/codes/iecc/concepts/

Fenestration Haze Factor (CB-6) 

Objective: Clarify the testing requirements for fenestration haze factor to reference 

Procedure A of ASTM D 1003 or other ASTM standards as applicable. 

Suggested Code Change Proposal 

Revise Section C402.3.2.2 as follows: 

C402.3.2.2 Haze factor. Skylights in office, storage, automotive, service, manufacturing, nonrefrigerated warehouse, retail store and distribution/sorting area spaces shall have a glazing materials or 

diffuser with a measured haze factor greater than 90 percent when tested in accordance with Procedure A

of ASTM D 1003. 

Exception: Skylights designed installed in such a manner as to exclude direct sunlight entering 

the occupied space by use of fixed or automated baffles, or the geometry of skylight and light 

well need not comply with Section C402.3.2.2. 

Reason: Clarification. The requirement for testing in the code eliminates the need to use the 

term “measured,” and could provide additional confusion should a user of the code interpret that 

as allowing post-installation measurement of haze factor in accordance with the standard. 

Procedure A covers testing and should be referenced. Also replacing “designed” with “installed 

in such a manner as” provides clarification as a skylight can be “designed” in the factory where 

the installation conditions in the exception may not be known. Those conditions are related to 

the installation of the skylight within the building and are more appropriately referenced in the 

code. 

(The information below is provided from the ASTM website for the referenced standard and is 

for informational purposes in considering further revision to this provision in the code. It 

appears to suggest that material with a haze value over 30 percent should not be tested to 

ASTM D1003 but rather to another test. This suggests the current code may be incorrect, but 

this is a technical issue that likely needs additional discussion.) 

Light that is scattered upon passing through a film or sheet of a material can produce a 

hazy or smoky field when objects are viewed through the material. Another effect can be 

veiling glare, as occurs in an automobile windshield when driving into the sun. 
Although haze measurements are made most commonly by the use of a hazemeter, a 

spectrophotometer may be used, provided that it meets the geometric and spectral 

requirements of Section 5. The use of a spectrophotometer for haze measurement of 

plastics can provide valuable diagnostic data on the origin of the haze, and Procedure B 

is devoted to the use of a spectrophotometer. 

Procedure A (hazemeter) test values are normally slightly higher and less variable than 

Procedure B (spectrophotometer) test values. 

Regular luminous transmittance is obtained by placing a clear specimen at some 

distance from the entrance port of the integrating sphere. However, when the specimen is 

hazy, the total hemispherical luminous transmittance must be measured by placing the 

specimen at the entrance port of the sphere. The measured total hemispherical luminous 

transmittance will be greater than the regular luminous transmittance, depending on the 

optical properties of the sample. With this test method, the specimen is necessarily 

placed at the entrance port of the sphere in order to measure haze and total 

hemispherical luminous transmittance. 

Haze data representative of the material may be obtained by avoiding heterogeneous 

surface or internal defects not characteristic of the material. 

Haze and luminous-transmittance data are especially useful for quality control and 

specification purposes. 

Before proceeding with this test method, reference should be made to the specification of 

the material being tested. Any test specimen preparation, conditioning, dimensions, or 

testing parameters, or combination thereof, covered in the materials specification shall 

take precedence over those mentioned in this test method. If there are no material 

specifications, then the default conditions apply. 

1. Scope

1.1 This test method covers the evaluation of specific light-transmitting and wide-anglelight-scattering properties of planar sections of materials such as essentially transparent 

plastic. Two procedures are provided for the measurement of luminous transmittance and 

haze. Procedure A uses a hazemeter as described in Section 5 and Procedure B uses a 

spectrophotometer as described in Section 8. Material having a haze value greater than 

30 % is considered diffusing and should be tested in accordance with Practice E2387. 

1.2 The values stated in SI units are to be regarded as standard. 

Note 1—For greater discrimination among materials that scatter a high percent of light 

within a narrow forward angle, such as is the case with abraded transparent plastics, 

adjust the hazemeter and perform measurements in accordance with Test Method 

D1044. 

1.3 This standard does not purport to address all of the safety concerns, if any, 

associated with its use. It is the responsibility of the user of this standard to establish 

appropriate safety and health practices and determine the applicability of regulatory 

limitations prior to use. 
Cost Impact: There is no cost impact associated with this proposed change.