## 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 meas ured 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 confus ion 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 t hat 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 integr ating sphere. However, when the specimen is hazy, the total hemispherical luminous transmi ttance 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 materi al may be obtained by avoiding heterogeneous
surface or internal defects not characteristic of the material.

Haze and luminous-transmittance data are es pecially 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, co vered 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 pl anar sections of materials su ch as essentially transparent plastic. Two procedures are provided for the measurement of luminous transmittance and
haze. Procedure A uses a hazem eter 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 mate rials 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 addres s all of the safety concerns, if any,
associated with its use. It is t he responsibility of the user of this standard to establish appropriate safety and health practices an d determine the applicability of regulatory limitations prior to use.Cost Impact: There is no cost impact associated with this proposed change.