If I am reading this correct, medical vacuum exhaust can be made of any material the manufacturer0 determines? Just looking for your input.

5.1.3.7.1  Medical–Surgical Vacuum Sources.

5.1.3.7.1.1  Medical–surgical vacuum sources shall be located per 5.1.3.3 as follows: 

(1) 

Indoors in a dedicated mechanical equipment area, adequately ventilated and with any required utilities

(2) 

In a room ventilated per 5.1.3.3.3.2

(3) 

For air-cooled equipment, in a room designed to maintain the ambient temperature range as recommended by the equipment manufacturer

5.1.3.7.1.2  Medical–surgical vacuum sources shall consist of the following: 

(1) 

Two or more vacuum pumps sufficient to serve the peak calculated demand with the largest single vacuum pump out of service

(2) 

Automatic means to prevent backflow from any on-cycle vacuum pumps through any off-cycle vacuum pumps

(3) 

Shutoff valve or other isolation means to isolate each vacuum pump from the centrally piped system and other vacuum pumps for maintenance or repair without loss of vacuum in the system

(4) 

Vacuum receiver

(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

(6) 

Except as defined in 5.1.3.7.1.2(1) through (5), materials and devices used between the medical vacuum exhaust and the medical vacuum source that are permitted to be of any design or construction appropriate for the service as determined by the manufacturer

Larry,

Yes, it is also my understating that the manufacturer can use whatever materials they deem appropriate for the exhaust on their manufactured skid.

However, it is also my understanding:

The plumber who ties into the skid and runs the piping outside must use materials defined in 5.1.10.2. 

I have always looked at it like Peter as far as what the manufacture can do on the skid vs what the installer can do in the field. 

Exploring different code editions makes it more interesting...

2021:

5.1.3.7.7.7 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.

2018:

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.

2015: 

5.1.3.7.6.6 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.

2012:
No section

2005:

5.1.3.6.7.4 The exhaust shall be piped of materials approved

for medical–surgical vacuum piping under 5.1.10.2.

So we have to go back to the 2005 and earlier to get the "shall" requirement for the vacuum exhaust. (All still have the same/similar wording of 5.1.3.7.1.2 (6)).
The 2012 we only have what is in 5.1.3.7.1.2 (6). 2015-2021 adds the clarification of 5.1.10.2/5.1.10.3 but we have that dreaded "shall be permitted" wording.

So I can see where you could fall in Peter's camp as well as Mark's camp with neither being incorrect. (I know, super helpful)

While on the "shall be permitted" wording....in the 2012-2018 editions do you have to deburr the copper tubing? ;)