A new standard for determining load calculations will be developed byASHRAEin cooperation with theAir Conditioning Contractors of America (ACCA), according to a joint statement from the organizations.

Proposed Standard 183P, "Methods and Procedures for Performing Peak Heating and Cooling Load Calculations," released by ASHRAE for public comment in May, will be processed through ASHRAE's standards writing procedures as an American National Standard.

As part of the agreement to cooperate, the membership of the ASHRAE 183P committee will be expanded to include three members nominated by ACCA and the proposed standard will reference the cooling load temperature difference (CLTD) load calculation method provided in ACCA's Manual N.

ACCA has announced it will withdraw its intent to submit a revision to its Manual N "Load Calculations for Non-Residential Buildings, Three Stories and Less" as an American National Standard.

"A single standard for nonresidential load calculation procedures will improve the accurate determination of system and equipment sizes for all types of buildings," said Ronald P. Vallort, P.E., ASHRAE president. "Having ACCA's cooperation in development of the ASHRAE standard reflects the importance of having HVAC contracting and engineering communities work together in areas of mutual interest."

The proposed standard will be designated ANSI/ASHRAE/ACCA Standard 183 when approved.

"ACCA's goal is to ensure that contractors have access to the most accurate, efficient, and effective design standards," said Greg Leisgang, ACCA 2005-2006 chairman. "It is ACCA's intent to assure that the proposed standard meets the needs of contractors who would use this standard for light commercial building load calculations."

The proposed standard will be further developed by the expanded project committee to incorporate the recommendations of both organizations.

Proposed Standard 183P does not dictate a particular load calculation method or program but does establish a minimum level of care that would apply to any method. The proposed standard seeks to establish the criteria of an appropriate calculation process that will result in an accurate estimate of the air conditioning and heating load in a building.