Updating the building code to save energy.

It is heartening to see how the building design and construction community has embraced the idea of sustainable design.

Owners, developers, the government, and design professionals are all very interested in building "green." In New York City, however, these professionals are sometimes up against institutional and legal obstacles that force them to make choices that are contrary to sustainable best practice.

The provisions of the New York City Fire Department Rules and Regulations that require a licensed refrigeration engineer to constantly man certain refrigeration and air conditioning systems are a prominent example.

New York City is one of the places where the use of central air conditioning is vital. In the early days, building air conditioning systems were designed and constructed using individual components connected by hundreds of feet of piping and fittings. The system was filled with refrigerants ranging from flammable and poisonous ammonia to toxic mixtures of Freon-based gases operating at high pressures.

Continual leaks from seals and fittings were the norm and catastrophic failures were not uncommon. To function safely and efficiently, these systems needed skilled operators since automated controls were crude or nonexistent.

To deal with these concerns, provisions were added to the New York City Fire Department Regulations requiring that these systems only be operated in the presence of a licensed refrigeration engineer. (NYC Rules and Regulations Title 3 Fire Department, Chapter 33 Refrigeration, III 33-03 "Qualified Refrigerating Machine Operator Requirements").

For buildings that operate their systems 24 hours a day, such as museums, hospitals, or residential towers, multiple shifts of licensed engineers were needed. The regulations dictated that if a system contained a single compressor of 50 horsepower or greater, or that the combined horsepower of all the compressors in the building exceeded 100 horsepower, a licensed operator was required. (Office buildings as small 30,000 s/ f would generally require systems of this size.) Compressors less than 15 horsepower were excluded from the 100 horsepower total, so small buildings and buildings using incremental units, such as window units or packaged units, were not burdened by this rule.

Over the years, there have been great strides in the development of refrigeration and air conditioning equipment. By using advanced design and construction techniques, manufacturers are providing large, central station equipment that uses less than 50% of the power that was required 30 years ago.

Whereas systems of the past were comprised of many individual components, today's systems are usually factory assembled with few or no field connections. Controls are highly automated using computers and Internet communications. Modern equipment rarely leaks and catastrophic failures are rare.

Manufacturers are also using refrigerants that are much friendlier to the atmosphere. As a result, central station equipment no longer needs the same hands-on supervision to run safely and efficiently.

Unfortunately, the regulations have not kept pace with the improvements in technology. New York City is still bound by archaic rules requiring a licensed operator for all but the smallest systems.

To circumvent this requirement, owners and designers design central systems for large buildings using many small, relatively inefficient compressor units of less than 15 horsepower. The so-called modular chiller, or New York City unit, is a result. Unfortunately, this technology uses the least efficient compressor technology, such as rotary and scroll compressors.

The result is a chiller that does not need a licensed engineer for its operation but uses 50% to 80% more energy than its larger, more efficient capital costs as well as operating costs. These are extra dollars that could be targeted for other sustainable technology for the building.

Clearly, safety is a major concern in the operation of building systems. However, the current regulations are outdated.

Whereas laws across the nation require licensed operators for high pressure boilers, only New York City requires engineers for relatively small refrigeration equipment. By updating or eliminating these provisions, the Fire Department of New York City will do much to advance energy conservation and sustainable design goals while reducing the cost of building construction.

DOMINICK DEPINTO, PARTNER, AMBROSINO, DEPINTO & SCHMIEDER CONSULTING ENGINEERS