Selecting the Correct Pressure Rating For Your Plumbing Job
When it comes to plumbing, one of the key factors to consider is the required pressure rating for your system. Choosing the correct pressure rating will help reduce the risk of pipe failures, expensive maintenance, and overall safety. Whether you’re working on a residential plumbing job or large scale infrastructure, we can help supply the best piping for your needs.
A pressure rating is the maximum internal pressure a pipe or component can safely withstand without failure. There are a few components that influence pressure ratings, which we’ve broken down below.
Pressure Rating Terminology
- Working Pressure (PSI/Bar/PN): This is the maximum continuous pressure a pipe is designed to handle under normal operating conditions. It’s often expressed in pounds per square inch (PSI), bar (metric), or Pressure Nominal (PN) for some plastic pipes.
- Burst Pressure: This is the pressure at which a pipe is expected to rupture. There’s typically a safety factor built in, meaning the burst pressure is often 2-3 times higher than the rated working pressure.
- Standard Dimension Ratio (SDR): For some plastic pipes (like PVC), SDR is used to express the relationship between the pipe’s outer diameter and its wall thickness (SDR = OD/wall thickness). A higher SDR number indicates a thinner wall and thus a lower pressure rating. For example, SDR 26 has a lower pressure rating than SDR 17.
- Pipe Schedule: This number (e.g., Schedule 40, Schedule 80, Schedule 160) indicates the wall thickness of the pipe. A higher schedule number means a thicker wall, resulting in a smaller internal diameter but greater strength and pressure resistance.
- Schedule 10: Thin-walled, typically for low-pressure applications where weight and cost are concerns.
- Schedule 40: Considered “standard,” used for a wide range of medium-pressure applications.
- Schedule 80: “Extra strong,” thicker walls for higher pressure or increased toughness.
- Schedule 160: The thickest standard wall, “double extra strong,” for very high-pressure requirements.
Selecting the Correct Pressure Rating For Your Job.
- Safety: The paramount concern. Undersized or under-rated pipes can lead to catastrophic failures, leaks, bursts, and potential harm to personnel and property.
- System Integrity: Ensures the piping system remains structurally sound and functions as intended over its lifespan.
- Longevity: Properly rated pipes are less susceptible to stress, fatigue, and premature failure, extending the system’s operational life.
- Compliance: Meeting industry standards and regulatory requirements for safe operation.
Popular Pipes and Their Common Applications.
- PVC sewer pipe is used for the collection of waste and stormwater from domestic sources. Available in 3”, 4”, and 6”, solid or perforated, in triple wall and solvent.
- ASTM Solvent Weld PVC Pipe is used for residential, commercial, industrial, and agricultural waste water and other non-pressure applications. Available in 3″, 4″, and 6″ in both solid and perforated.
- SDR 26, SDR 28, and SDR 35 Gasketed Sewer Pipe is used for gravity storm and sanitary line, gravity industrial lines, and private drain connections. Available from 4″ to 24″ in diameter, and certified to CSA B182.2 and ASTM D3034.
- Schedule 40 and Schedule 80 Pipe is intended for pressurized applications. SCH 40 is ideal for residential plumbing and drainage, while SCH 80 is fore high-pressure industrial applications.
If you’ve got an upcoming plumbing job and would like some additional advice, our plumbing expert George is available by phone or email to help you make the best purchasing decision for your plumbing job. He’s got over 40 years in the plumbing industry, and a full yard of inventory to keep you moving.
