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Pipe Fitting Buying Guide

Before beginning any do-it-yourself plumbing project, it's important to know the different types of pipes used to transport water and waste in and out of your home.

Pipe Fitting Buying Guide

Types of Piping Systems

Most homes built since the mid-1970s have plastic pipes and fittings, which are rated by the American Society for Testing and Materials (ASTM). Plastic pipes can be used for pressurized applications, such as potable (drinking) water systems, hot-and-cold water distribution and irrigation systems. They can also be used for nonpressurized applications (gravity flow), such as sewage, drainage and storm drain systems. Older homes built before 1960 used galvanized steel or cast-iron pipes for DWV (drain / waste / vent) systems. DWV systems remove wastewater and prevent the flow of sewer gases into the home. The most common type of pipes used in homes today are copper and PVC (polyvinyl chloride), which are strong, long-lasting and easy to install.

Materials for DWV Pipes

  • Cast-iron pipe and fittings (black)
  • PVC Schedule 40 DWV pipe and fittings (white; used in irrigation, underground sprinkler systems, swimming pools, outdoor applications and cold-water supply lines)
  • ABS DWV pipe and fittings (black, common in the western U.S.)

Materials for Pressurized Systems

  • PVC Schedule 40 (SCH 40) pipe and fittings (white; straight, angular turns; designed for potable water under pressure into buildings)
  • CTS CPVC pipe and fittings (cream or tan; used for hot or cold water; sized the same as copper)
  • PVC Schedule 80 (SCH 80) pipe and fittings (dark gray; withstand higher pressure; designed for the distribution of pressurized liquids)

PVC SCH 40 DWV Pipe and PVC DWV Fittings for Nonpressurized Applications

PVC DWV fittings can be installed with foam core pipe or dual-marked solid-wall pipe. ASTM F 891-rated foam core pipe is lighter and less expensive. Solid-wall PVC pipe is often rated for both pressurized (ASTM D 1785) and nonpressurized (ASTM D 2665) applications (often referred to as dual-marked). When solid-wall or foam core pipe is used with PVC DWV fittings, the resulting system isn’t pressure-rated.

Description

  • White, rigid pipe and fittings
  • Joined with solvent cement, conforming to applicable ASTM standards
  • Have a gradual, sanitary turn

Application

  • Drain household sanitary waste (kitchen, bathroom) and groundwater
  • Not for pressurized applications or compressed air / gasses

Joining Method

  • Solvent cements must meet ASTM D 2564 standard
  • Primer is required
  • May be joined with a slip-joint compression fitting (a trap adapter)
  • Threading PVC 40 pipe isn’t recommended
  • MIP (male iron pipe size) and FIP (female iron pipe size) adapters are available

PVC SCH 40 Pipe and Fittings for Pressurized Applications

Description

  • White, rigid pipe and fittings
  • Joined with solvent cement, conforming to ASTM D 2564 standard
  • Have straight, angular turns
  • Not for gradual sanitary turns for pressure systems

Application

  • Distributable potable water under pressure into a building (not to be used inside)
  • Irrigation and sprinkler systems
  • Draining condensate waste from heating and air conditioning systems
  • Not for compressed air or gasses

Joining Method

  • Solvent cements must meet ASTM D 2564 standard
  • Primer required
  • May be flanged with SCH 80 flanges
  • Threading PVC 40 pipe isn’t recommended
  • MIP and FIP adapters are available

PVC SCH 80 Pipe and Fittings for Pressurized Applications

Description

  • Dark gray, rigid pipe and fittings
  • Joined with solvent cement conforming to ASTM D 2564 standard
  • Straight, angular turns must be used

Application

  • Distribution of pressurized liquids
  • Can be used in industrial applications
  • Not for use with compressed air or gasses

Joining Method

  • Solvent cements must meet ASTM D 2564
  • Primer should be IPS (iron pipe size) P-70 or Oatey Industrial-grade
  • May be flanged with SCH 80 flanges
  • Threading PVC 80 pipe can be done
  • MIP and FIP adapters are available

ABS Foam Core SCH 40 DWV Pipe and ABS DWV Fittings for Nonpressurized Applications

Description

  • Black, rigid pipe and fittings
  • Joined with solvent cement conforming to ASTM D 2235 standard
  • Fittings have a gradual sanitary turn

Application

  • Drain household sanitary waste (kitchen, bathroom) and groundwater
  • Not for use with pressurized applications or compressed air / gasses

Joining Method

  • Solvent cements must meet ASTM D 2235 standard
  • Primer isn’t recommended
  • May be joined with a slip-joint compression fitting (a trap adapter)
  • Threading ABS-40 foam core pipe isn’t recommended
  • MIP and FIP adapters are available

CTS CPVC Pipe and Fittings for Pressurized Hot-and-Cold Water Applications

Description

  • Cream or tan, rigid pipe (with a gold stripe) and fittings
  • Joined with solvent cement conforming to ASTM F 493 standard

Applications

  • Distribute hot-and-cold potable water under pressure
  • Not for use with compressed air or gasses

Joining Method

  • Solvent cements must meet ASTM F 493 standard
  • Yellow FlowGuard Gold cements may be used without primer, where approved by code
  • Compression fittings with a brass ferrule may be used
  • Threading the pipe isn’t recommended. Use CTS CPVC male adapters in cold-water applications only. Use CTS CPVC brass-threaded transition fittings for hot-water applications
Caution

Don’t use compression fittings with brass ferrules to connect to CTS CPVC pipe or fittings where water temperatures exceed 140°F