2021 Codes

5.1.3.7.7.6 Vacuum exhaust piping shall be permitted to be made of materials and use a joining technique as permitted under 5.1.10.2 and 5.1.10.3.

5.1.3.7.1.1 Medical–surgical vacuum central supply systems shall consist of the following:

(5) Piping between the vacuum pump(s), discharge(s), receiver(s), and vacuum source shutoff valve in accordance with 5.1.10.2, except brass, galvanized, or black steel pipe, which is permitted to be used as recommended by the manufacturer

Proposed 2024 code changed to:

5.1.3.7.7.6 to:

Vacuum exhaust piping shall be permitted to be made of brass, galvanized, black steel, or materials and a joining technique as permitted under 5.1.10.2 and 5.1.10.3.

Reason for change:

Many installers or design engineers perceive a conflict between 5.1.7.7.6 and 5.1.3.7.1.1 (5).

5.1.3.7.7.6, allows vacuum exhaust piping to be made of copper tubing, stainless, or CMT.

5.1.3.7.1.1 allows brass, galvanized, or black steel between the vacuum pump and the "discharge." 

Some will debate the definition of discharge vs. exhaust.  The context of 5.1.3.6.3.11 describes vacuum "discharge" as the outside termination of the vacuum exhaust typically on the roof.