The main trunk line of an air conditioning supply system requires some form of adhesive to secure the smaller duct lines that branch out into it. Tape is usually more effective on round ducts than on the sharp, uneven corners of rectangular ducts. Closure systems used with flexible air ducts and connectors must comply with the UL 181B standard and bear the marks 181B-FX for pressure sensitive tape or 181B-M for putty. Aluminum foil tape (also known as “plenum on a roll”) is easier and less messy, but it tends to fail faster due to delamination and dirt and grease in the ducts. Putty sealants are often a more cost-effective option than professional HVAC tapes, but they may not be as durable.
Not only must each section of the duct be sealed with the next, but the joints of each duct must also be sealed. Closure systems used with rigid fibrous glass ducts must comply with the UL181A standard and bear marks 181A-P for pressure sensitive tape, 181A-M for putty or 181 A-H for thermosensitive tape. Fiberglass plate joints must use fiberglass mesh and putty to form a UL-181 seal. If you are going to use putty to seal joints in fiberglass plate ducts, use fiberglass mesh tape for all joints.
When it comes to sealing ducts in residential homes, few building inspectors outside of California enforce current code requirements that require residential duct joints to be sealed with high-quality putty or adhesive tape. If yours are different, you may need to replace the boots or seal the gaps with spray foam, putty, or canned adhesive tape. I am considering sealing all the ducts in my house, which according to the HVAC system are 100% fiberglass plates joined together and connected with adhesive tape. Unfortunately, however, few building inspectors outside of California bother to enforce current code requirements that require residential duct joints to be sealed with high-quality putty or adhesive tape.
Sean Sean's question relates to another blog. However, it was so broken that the grill was sealed, and now that I've sealed it with putty (not very well as you can see in the picture, it needs another layer on top of the fiberglass tape), I have no idea how to put the grill back in without caulking again. At that time, the duct can be attached to the trunk and the seam can be properly sealed before repairing the roof. When it comes to sealing air conditioning ducts, there are several options available depending on your needs and budget.
Professional HVAC tapes can stand up to wear and tear but may be more expensive than putty sealants. Putty is often a more cost-effective option but may not be as durable as professional HVAC tapes. Fiberglass plate joints must use fiberglass mesh and putty to form a UL-181 seal for maximum effectiveness. No matter which option you choose, it is important to ensure that all sections of the duct are properly sealed with either pressure sensitive tape, putty or thermosensitive tape.
Additionally, all joints must also be sealed using either fiberglass mesh tape or putty for maximum effectiveness. When it comes to sealing residential homes, few building inspectors outside of California enforce current code requirements that require residential duct joints to be sealed with high-quality putty or adhesive tape.
