Architects and MEP engineers more than any other members of the industry determine the energy efficiency, life-cycle cost, and indoor air quality of buildings. Within the cost limits set by the building owner, architects and engineers are responsible for defining buildings that achieve the best possible performance in terms defined as “Sustainable” and “Green.” Hence, trade-off evaluations between performance and costs are essential parts of successful building design.
Many of the steps necessary for achieving high building performance require “high tech” and expensive components. Others simply require the elimination of detrimental and outdated design practices. The practice of including the failure prone p-trap in the design of air conditioner drain systems is an example of outdated design practices.
The propensity for p-trap failures and some of the consequences are documented in ASHRAE [American Society of Heating, Refrigerating and Air Conditioning Engineers] Standard 62-89R, paragraph 5.6.4, which reads as follows:
"Condensate traps exhibit many failure modes that can impact on indoor air quality. Trap failures due to freeze-up, drying out, breakage, blockage, and/or improper installation can compromise the seal against air ingestion through the condensate drain line. Traps with insufficient height between the inlet and outlet on draw-through systems can cause the drain to back-up when the fan is on, possibly causing drain pan overflow or water droplet carryover into the duct system. The resulting moist surfaces can become sources of biological contamination. Seasonal variations, such as very dry or cold weather, may adversely affect trap operation and condensate removal."
Despite this assessment, the condensate trap remains the choice of many architects and engineers as a means of condensate drainage control. This choice, unfortunately, deprives your clients of high performance buildings and any hope of reaching the level of truly “sustainable green buildings”. Some of the many trap failure modes identified by ASHRAE are illustrated in Figure 1. These failure modes, which occur frequently, allow condensate blowing and flooding as illustrated—causing property damage and air contamination. Since all the air in a building passes through the air conditioning unit at a rate of several times per hour, the circulated health threatening pathogens inevitably expose occupants to degraded indoor air quality, as indicated in Figure 2.
Architects and engineers must reject the common practice of specifying p-traps for condensate drain systems and seek an effective and reliable alternative. The CostGard™ Condensate Drain Seal is such an alternative. Tens of thousands are performing successfully in locations throughout the United States, in all kinds of environments: hot and humid to cold and dry. Not one has failed to operate successfully.
Specifying condensate drain systems with the CostGard™ Condensate Drain Seal can be as simple or as formal as the designer desires.
For guidance in preparing a more formal specification, go to: CSI Specification and Drawings. Please contact us with any questions regarding the CostGard™ Condensate Drain Seal and preparation of specifications.
For the most commonly used Unitary Rooftop Units (RTUs)—up to 30 tons—detailed system designs and installation instructions are readily available. Refer to: Products- RTU - Unitary Rooftop - up to 30 Tons for a list of the available designs. For these units, the designer may simply define the RTU model and state:
"The condensate drain system shall incorporate the CostGard™ Condensate Drain Seal by Trent Technologies, Inc., Tyler, TX. Phone: (903) 509-4843."
The only constraint on this statement is that the curb height must be adequate to accommodate the drain seal, which is 5.6 inches deep.
In instances where detailed system designs and installation instructions are not available, the same simple statement can be used. Trent Technologies will work with the contractor and designer to define the design and installation instructions necessary to provide a successful condensate drain system.