Pitts Seam Sealant

Sealing in the Pocket

Applying Sealant into the Pittsburgh Seam is different than applying it on the Pittsburgh Lock but either means accomplishes the same result.
This image shows Exterior view of Pittsburgh’s Female Pocket with the Pitts Seam Sealant clearly visible at top near where the Longitudinal Seam and the Transverse Connector (TDC in this photo) nearly intersect  

SMACNA stipulates that the longitudinal seam be sealed with mastic on all Medium Pressure Duct (3” wg – 6” wg) this means that only low pressure duct (2” wg or less) is exempt. Most contractors seal this seam externally by way of Bucket and Brush and they do this either in their fab shop or on the job site. Some contractors are doing the same thing by way of Spraying it on from a 5 gallon container and doing this in their fab shop.

Many large contractors however apply the Sealant internally by having a Pitts Seal Sealant Application set up in their Coil Line to pump from a 5 gallon sealant into the female leg of the Pitts Lock; others do this same application manually with the use of use a cartridge gun.