Air Gaps?

Copyright 2012, NYS Capital Region Chapter of ASPE. All rights reserved.                 By: Douglas A. Page, P.E., MPA, LEEDap, CEM, CPD


Air Gaps?

This month's Code Tidbit reflects the dangers of not keeping up with the Code...


For the last few decades, condensate drainage from air handlers and terminal units (heat pumps, furnaces with  AC, etc.) has been treated as indirect waste. In my youth, I was taught by some really smart plumbers that this meant an air gap - of at least one pipe diameter. I once thought it was based on some Plumbing Code or some State/ NYC Department of Health's regulations as it related to food services. To reassure myself, I cracked open my State Sanitary Code for Food Service Establishments (aka., Public Health Law, Section 225, Subpart 14-1). If you lack a hard copy, it is at:


So subsection 14-1.141 of the Health Law says,

"14-1.141 Definition of indirect drain.

An indirect drain is a waste line which does not connect directly with the drainage system, but conveys and discharges liquid wastes through an air break into an approved plumbing fixture or receptacle, directly connected to the drainage system." Continuing the Code search, 9 NYCRR Subtitle S Chapter I Subchapter B Subsection 903.27 (aka., the old Green Book circa 1984) defines indirect waste pipes as "discharge through an air break…" It further defines 'air break' as "… terminating the open end of the pipe at least one inch above the flood rim of the receiving



Still not good enough? How about the 1977 really old yellow book (aka., the Code Manual for the State Building Construction Code) which was generated by the Division of Housing and Community Renewal (DHCR). On a side item, I attended training sessions sponsored by DHCR in NYC many years ago. In many ways, they were the keepers of the NYS Code - but I digress. Page 3 of Chapter 5 indicates, "…Every water outlet shall be protected, preferably by having the outlet end, from which water flows, terminate sufficiently above the flood rim of the receptacle to provide an effective air gap…"

Well, we could keep going. Somewhere, in some code, it probably required a gap of one pipe diameter. We could argue about the one inch air gap compared to a one pipe diameter, but our historical records appear to require some sort of Air Gap. Along comes the NYS adoption (with NYS enhancements) of the International Plumbing Code. The Current NYS Plumbing Code is based on the 2006 IPC. Chapter 8 discusses Indirect/Special Wastes. Section 802.1.5 references NONPOTABLE clear-water waste. It states:


"§P802.1.5 Nonpotable clear-water waste. Where devices and equipment such as process tanks, filters, drips and boilers discharge nonpotable water to the building drainage system, the discharge shall be through an indirect waste pipe by means of an air break or an air gap."

This section references an air gap or an AIR BREAK. The IPC defines an air break as:

"AIR BREAK (Drainage System). A piping arrangement in which a drain from a fixture, appliance or device discharges indirectly into another fixture, receptacle or interceptor at a point below the flood level rim and above the trap seal."

For our purpose, the key phrase is "below the flood rim." In short - no air gap.

Recently, I had to take a LEAP backward (Leap Year Humor). After telling our staff we needed an air gap for cooling coil condensate drainage, I needed to actually read the Code and discover an air break was just fine.

802.1.5 of the Code references Non-Potable ClearWaterWastes. It is explicitly for clear waste where these is no potential for contamination of the potable water supply. Section 802.1.3 is for PotableWastes that could contaminated and result in contamination of the potable water system. It reads:


"§P802.1.3 Potable clear-water waste. Where devices and equipment, such as sterilizers and relief valves, discharge potable water to the building drainage system, the discharge shall be through an indirect waste pipe by means of an air gap."

If you don't like my interpretation that cooling coil condensate is non-potable, give me a call. Please keep in mind that the Code defines potable water as:

"POTABLE WATER. Water free from impurities present in amounts sufficient to cause disease or harmful physiological effects and conforming to the bacteriological and chemical quality requirements of the Public Health Service DrinkingWater Standards or the regulations of the public health authority having jurisdiction."

In short , draining of stuff like HVAC cooling coils can be done through an air break (or air gap), and draining stuff like Sterilizers or ice machines that use potable water need to be indirect waste via an air gap. The EPA was working on new rules to cut down on the clear wastes going to sanitary. Per the 2006 IPC Commentary, potable clear wastes are not required to be discharge to sanitary.


Keep up the good work-


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