Understanding SDR Ratings

SDR (Standard Dimension Ratio) is the ratio of pipe diameter to wall thickness.

SDR Formula

SDR = OD / Wall Thickness

Example: 2" SDR 11 Pipe

2.375" OD / 0.216" Wall = 10.996 (SDR 11)

A lower SDR number means a thicker wall and higher pressure rating. A higher SDR means a thinner wall and lower pressure rating.

SDR Pressure Rating (PSI) Typical Use
SDR 7 333 PSI High-pressure force mains
SDR 9 250 PSI Municipal water mains
SDR 11 200 PSI Water service, irrigation
SDR 13.5 160 PSI Medium pressure systems
SDR 17 125 PSI Low-pressure distribution

Understanding SIDR Ratings

SIDR (Standard Inside Dimension Ratio) is pipe sized by controlled inside diameter, used primarily for turf irrigation and insert fitting applications.

SIDR Formula

SIDR = ID / Wall Thickness

Key Difference from SDR:

SDR uses Outside Diameter while SIDR uses Inside Diameter. For a given nominal size, SIDR pipe has a constant ID regardless of pressure rating.

A lower SIDR number means thicker walls and higher pressure capacity. SIDR pipe is manufactured to ASTM D2239.

Why Use SIDR Pipe?

  • Consistent Flow: Constant ID means predictable flow rates regardless of wall thickness
  • Insert Fittings: ID-controlled sizing works perfectly with barbed/insert fittings
  • Irrigation Systems: Ideal for turf and agricultural irrigation where flow consistency matters
  • Saddle Tees: Works with saddle-type tapping tees for branch connections
SIDR Pressure (PSI) Application
SIDR 7 250 PSI High-pressure irrigation mains
SIDR 9 200 PSI Commercial irrigation systems
SIDR 11.5 160 PSI Medium-pressure distribution
SIDR 15 100 PSI Standard turf irrigation
SIDR 19 80 PSI Low-pressure irrigation

ASTM D2239 Standard

SIDR pipe is manufactured to ASTM D2239 - "Standard Specification for Polyethylene (PE) Plastic Pipe (SIDR-PR) Based on Controlled Inside Diameter." This standard defines dimensions, tolerances, and pressure ratings.

Industry Note

SIDR was removed from AWWA C901 in the 2020 revision for potable water service. For potable water applications, use CTS or IPS pipe per current AWWA standards.

Reference: Plastics Pipe Institute | ASTM D2239

Understanding CTS Sizing

CTS (Copper Tube Size) PE pipe has outside diameters matching copper tubing, allowing use of standard copper compression fittings for potable water service.

What is CTS?

CTS pipe has an outside diameter (OD) that matches standard copper tubing dimensions. This allows PE pipe to be used with the same compression fittings and connections designed for copper tube.

Key Benefit:

Use brass or plastic compression fittings designed for copper tube - no special PE fittings required for water service connections.

CTS Applications

  • Potable Water Service: Water service lines from main to building
  • Meter Connections: Direct connection to water meters
  • Corporation Stops: Tapping connections at water mains
  • Curb Stops: Service shutoff valve connections

Applicable Standards

ASTM D2737
PE tubing dimensional standard for CTS sizing
AWWA C901
PE pressure pipe ¾" through 3" for water service
NSF/ANSI 61
Drinking water health effects certification
Nominal Size CTS OD (in) IPS OD (in)
½" 0.625 0.840
¾" 0.875 1.050
1" 1.125 1.315
1¼" 1.375 1.660
1½" 1.625 1.900
2" 2.125 2.375

CTS = Copper Tube Size (matches copper OD) | IPS = Iron Pipe Size (matches steel/iron OD)

PE4710 Material

QualPol CTS potable water pipe is manufactured from PE4710 high-density polyethylene with 1,600 psi Hydrostatic Design Basis. Cell classification per ASTM D3350 = 445574C.

AWWA C901-25

The current AWWA C901 standard covers PE pressure pipe ¾" through 3" for potable water, reclaimed water, and wastewater service. CTS sizing is the primary dimensional standard for water service tubing.

Reference: American Water Works Association | Plastics Pipe Institute

Certifications & Compliance

QualPol products meet or exceed industry standards for quality, safety, and performance.

NSF/ANSI 14

Certified for plastic piping system components and related materials. Ensures product safety and quality for potable water applications.

Products: Pressure Pipe, Potable Water Pipe, Turf Irrigation

NSF/ANSI 61

Drinking water system components certified for health effects. Validates materials are safe for contact with drinking water.

Products: Potable Water Pipe, Turf Irrigation

AWWA C901/C906

American Water Works Association standards for polyethylene pressure pipe and fittings for water service and distribution.

Products: Pressure Pipe, Potable Water Pipe

ASTM D3035

Standard specification for polyethylene plastic pipe based on controlled outside diameter. Defines dimensions and tolerances.

Products: All HDPE Pressure Products

PE4710 Material

High-performance polyethylene with 1,600 psi Hydrostatic Design Basis at 73°F. Superior strength and long-term performance.

Products: Pressure Pipe, Potable Water Pipe

BABA Compliant

Build America, Buy America Act compliant. Manufactured in Jerome, Idaho, USA with domestic materials for federally funded projects.

Products: All Products

Need Certification Documentation?

We provide certification letters, compliance documentation, and test reports for project submittals. Contact us with your specific requirements.

Request Documentation

Installation Guidelines

Based on PPI (Plastics Pipe Institute) Handbook of PE Pipe and AWWA M55 standards. See plasticpipe.org for complete documentation.

Handling & Storage

  • Store pipe on flat surfaces; use blocks and supports to prevent rolling or deformation
  • Avoid dragging pipe over rough surfaces; use appropriate lifting equipment for pipe over 8" diameter or 6 lbs/ft
  • Keep pipe away from petroleum products and solvents (do not heat fuse hydrocarbon-permeated pipe)
  • Inspect pipe for damage and clean debris from inside before installation
  • Do not exceed manufacturer's minimum bend radius when handling coiled pipe

Trenching Requirements

  • Trench width at pipe grade: OD + 12" minimum
  • Cover depth: 2.5' to 25' typical; minimum 3.0' under vehicle traffic
  • Bedding: Coarse-grained soil (gravel/sand); max particle size ½" for 2-4" pipe, ¾" for 6-8" pipe, 1" for larger
  • Embedment in 6" lifts, compacted to 85% Standard Proctor (95% under roads)
  • Final backfill: No stones larger than 8", organic material, or construction debris

Joining Methods

  • Butt Fusion: Most common method; heat pipe ends, press together under pressure to create permanent joint (per PPI TR-33, ASTM F2620)
  • Electrofusion: Uses prefabricated fittings with heating coil; ideal where butt fusion is impractical
  • Socket Fusion: Best for smaller diameter pipes requiring direction changes
  • Mechanical: Compression fittings with seal/grip rings for fast or removable connections

Hydrostatic Testing

  • Test at 1.5x system design pressure for up to 3 hours (per PPI TN-46)
  • Add water periodically to maintain pressure; initial stretching is normal PE behavior
  • Slight pressure decline during test is normal (visco-elastic creep), not a leak indication
  • Base test pressure on lowest-rated component in the system (fittings, valves)
  • Visual inspection of all fusion joints before burial; document test results