BUBBLE TIGHT DAMPERS FAQS
Answers to your most Frequently Asked Questions about Greenheck bubble tight dampers.
Q:
Q:Are bubble tight dampers tested at the factory before shipment?
A:
A:Yes, all bubble tight dampers are tested to AMCA Standard 500D for bubble tightness prior to shipment.  Testing certificates are shipped with the dampers to the job site.  Additional copies are kept at Greenheck if needed.
Q:
Q:Can Greenheck build Bubble Tight Dampers with heavier frame and blade gauges if required by the specifications?
A:
A:Yes, Greenheck can build dampers with heavier gauges if required by the specifications or if trying to meet the construction standards of another manufacturer. Contact the factory for special pricing.
Q:
Q:Do we meet ASME NQA- "Quality Assurance Program Requirements for Nuclear Facilities"?
A:
A:

The short answer is no, however, never give up on this account. Greenheck Industrial Dampers are manufactured under a certified ISO9001 Quality Assurance Program (QAP). This QAP is very stringent, but is not certified to NQA-1 per the DOE and NUPIC criteria. However, Bud Fabian and Yung Liu of Argonne National Laboratory summary in a 2006 paper titled Quality Assurance Standards ISO-9001 and ANSI/ASME NQA-1 – A Brief Comparison states:

 
The NRC recommends that should an ISO-9001 supplier be used, additional QA requirements must be added to the purchase order to assure compliance with Subpart H. The additional QA requirements should be part of a dedication process for commercial-grade items and activities. The ASME NQA-1-2004 has a comprehensive dedication process. (See Requirement 7, Section 700, and Non-mandatory Appendix 7A-2, for the dedication process. See NRC Generic Letters (GL) 89-02 and 91-05 for the common mistakes made by licensees using the dedication process.)
 
In summary, items and activities that are not important to (nuclear) safety can, in most cases, be purchased from an ISO-9001 supplier; however, additional QA requirements must be imposed on the ISO-9001 suppliers in the procurement of important-to-safety items and activities for Type B radioactive and fissile material transportation packaging. This is consistent with the approach described in NRC Regulatory Guide 7.10 (Rev. 2) and SECY-03-0117
 
Keeping in mind that most of your applications are not in nuclear facilities will also allow more leniency on using a quality program outside of the nuclear world, but still adhering to the integrity of the final product.

Q:
Q:My specification calls for "Pressure Decay Testing" do we do this?
A:
A:Pressure Decay testing is usually specified as ASME N510, Testing of Nuclear Air Treatment Systems. Pressure decay testing is a test method that pressurizes the damper frame cavity to 125% of the rated damper pressure and requires you to measure how long the pressure holds before reducing to 80% of its original value or 15 minutes (whichever is shorter). Then a calculation is performed to calculate the leakage rate in SCFM:
 
$$Qavg = {(Pi - Pf) * V \over (Ti  Tf) R *  Δt * 0.075} $$
 
If the damper is tested to zero bubble, then 15 minute criteria will always be used and the leakage rate will be zero. Therefore, as a general rule, we don’t test to the pressure decay method as the testing time and set up are longer and the test method doesn’t align with the bubble tight product requirements as it assumes some level of leakage. Pressure Decay testing can be provided at an added cost if the engineer absolutely requires it, contact the factory for pricing.
Q:
Q:My specification calls for bubble tight testing per ASME N509; do we comply with this?
A:
A:Both ANSI / ASME N509-2002, Nuclear Power Plant Air-Cleaning Units and Components, and ANSI / ASME N510-2007, Testing of Nuclear Air treatment Systems, reference leakage criteria given by ASME AG-1, Appendix DA-1. AG-1 allows up to a 1/16” dia. bubble in one second or 9/32” dia. bubble in 1 minute. If either of these is found, it is determined a leak exists. Greenheck tests to zero bubbles, and reworks any unit found to create any bubble, before shipment. Therefore, we do comply with the requirements of ASME N509.