Plumbing, Pumping

Piping details

Understand the various types of pipe and their applications
By Saahil Tumber, PE, HBDP, LEED AP, ESD, Chicago September 17, 2019
Figure 2: Shown are metal struts for supporting piping systems on slab. Lugged butterfly valves at the chilled water supply and return loops are also visible. Courtesy: ESD

Acrylonitrile butadiene styrene pipe is strong and impact-resistant. It is occasionally used for drain, waste and vent applications. ASTM standards D2661 and D3965 deal with ABS pipes. 

Chlorinated polyvinyl chloride has similar properties to PVC and is rated for higher pressures and temperatures. CPVC pipes and fittings are available with flame/smoke index less than 25/50 and therefore can be used in air plenums. 

When using CPVC pipes and fittings, it is critical that manufacturer data sheets be reviewed in detail, as not all pipe sizes and fittings are listed to meet the flame/smoke index threshold mandated by building codes. CPVC pipes are extensively used for industrial water applications associated with evaporative cooling systems such as those serving data centers. ASTM standards D1784 and D1785 deal with CPVC pipes.  

Cross-linked polyethylene (PEX) incorporates cross-link bonds in the structure of polyethylene. PEX pipe is strong and durable and can be used for fluids up to 200 F. Depending on the manufacturing process, PEX is classified as Type A (peroxide method), Type B (silane method) and Type C (electronic irradiation method) and properties such as flexibility, strength, thermal stability, repairability, etc. vary for each type. PEX is commonly used for radiant heating and cooling applications. ASTM standard F876, F877 and F2023 deal with HDPE pipes. 

Polyethylene and high-density polyethylene pipes are flexible, lightweight and durable. They are frequently used for underground water and drain applications. ASTM standard D2239 deals with PE and ASTM standard D3350 deals with HDPE pipes. 

Polypropylene pipe is lightweight and resistant to chemicals and can be used for higher-temperature applications compared to PVC. They are frequently used for corrosive and drainage applications. ASTM standards F2830 and F2389 deal with polypropylene pipes.  

Polyvinyl chloride is a commonly used pipe material due to its low cost. One of the big disadvantages of PVC is its inability to meet the flame/smoke index threshold of 25/50 as mandated by building codes for use in air plenums. ASTM standards D1784, D1785 and D2665 deal with PVC pipes. 


Saahil Tumber, PE, HBDP, LEED AP, ESD, Chicago
Author Bio: Saahil Tumber is technical authority at ESD. He is responsible for the overall design of mechanical systems for data centers, trading areas and other mission critical facilities requiring high availability. He is a member of the Consulting-Specifying Engineer editorial advisory board.