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[Dennis Maidon]

DuctMate Industries, Inc.



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From: Hinton, Billy [mailto:Billy.Hinton@ncdoi.gov]
Sent: Friday, February 03, 2012 4:01 PM
To: Grant Scorsone
Cc: Gentry, Susan; Dittman, Daniel E; Ewens, Samantha
Subject: FW: Request for Assistance

Mr. Scorsone, thank you for your email concerning your Ductmate Greenseam+ factory sealed low pressure duct product. You met with Mr. Dittman and I in our office to discuss the 2012 NC Mechanical Code requirements for sealing of duct systems and its relationship to your product. The circular metallic Greenseam+ duct system incorporates a patented internal sealing system that seals both transverse duct joints and longitudinal duct seams. The prescriptive sealing requirements of the 2012 NC Mechanical Code, section 603.9 would be considered to have been addressed for the joints incorporating this sealing feature. Generally, low pressure duct systems are sealed on the duct exterior with approved mastic or tapes that are visible to inspectors in the field when they verify proper sealing of ducts. Use of your product would require outreach by you to inspection departments to educate them on the features of your product, proper installation methods, and observable specific features that distinguish the Greenseam + product from normal low pressure duct. If inspectors cannot distinguish the joints specific to Greenseam+ sealing system, they will routinely require sealing on the duct exterior to verify proper sealing of ducts. Additionally, joints not incorporating the Greenseam+ feature would still require sealing in the traditional manner, such as joints that occur at terminal devices and expanding elbows for example. We cannot speak to how well your system performs with respect to leakage if asked, but it did appear robust in design. And we did not address your product structurally, but we understand you indicate it conforms to SMACNA requirements. Inspectors would also need to be trained how to observe that proper insertion of sleeved joints has been performed so that a proper joint has been made in the field. Inspectors may request additional information.

Mr. Dittman and I encouraged you to obtain an ICC Evaluation Report that addresses all aspects of your product with respect to all code requirements. ICC provides services at a fee for performing such reports for new products entering the market place. Generally, their review is thorough including review of testing as may be performed internal to your shop for duct leakage and analyses for structural integrity and material requirements. ICC reports are generally favored by inspection departments for their review and evaluation of specific products. These reports tend to address their questions.

The 2012 NC Mechanical Code does not prescribe a performance requirement for low pressure duct leakage performance, but the 2012 NC Energy Conservation Code (NCECC) does require a leakage test for low pressure duct located outside the building thermal envelope for residential buildings. Section 403.2.2 of the 2012 NCECC requires total duct leakage to be less than or equal to 6 CFM per 100 FT2 of conditioned floor area served by the system when tested at a pressure differential of 0.1 inches w.g. across the entire system, including the manufacturer’s air handler enclosure. Also, as a helpful note with respect to other jurisdictions outside of NC, those jurisdictions outside NC adopting the provisions of the 2009 IECC will also require a duct leakage performance test for low pressure duct systems in residential buildings.

Our department cannot provide endorsement or outreach for specific products of manufacturers. We do have a public web site that contains contact information for all jurisdictions we can refer you to: http://www.ncdoi.com...departments.asp

Also, various inspector associations conduct workshops for training and also conduct annual educational conferences that include trade shows for vendor products. I would recommend that you contact Mr. Dittman for information concerning the NC Mechanical Inspector Association Annual Educational Conference that will be conducted in August this year and plan to participate.

Best regards, Billy Hinton.


Billy Hinton, PE, PEM
Evaluation Services Section
NC Department of Insurance
Engineering Division
322 Chapanoke Road
Raleigh, NC 27603
1-919-661-5880 x-239
1-919-662-4414 FAX
Mail address:
NC Department of Insurance
OSFM
1202 Mail Service Center
Raleigh, NC 27699-1202