I do not know whether to use mastic or tape on this joint

Do not choose by what is nearby. Verify the seal class, pressure class, system type, and approved material before sealing.

Stop if

• What seal method applies here - mastic, listed tape, fabric-reinforced mastic, gasket, or something else?

Watch out

• Do not use random tape or mastic just because it is sitting nearby.

Check

• Identify the duct/system and location.
• Ask what seal class or approved sealing method applies.
• Check whether the material is listed/approved for this use.
• Use only the approved method after fit-up is clean and tight.
• If you do not know what seal class means, ask before starting.

Steps

• Identify the duct/system and location.
• Ask what seal class or approved sealing method applies.
• Check whether the material is listed/approved for this use.
• Use only the approved method after fit-up is clean and tight.
• If you do not know what seal class means, ask before starting.

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