Gas Piping Materials & Installation
Pipe types, sizing calculations, thread sealants, CSST bonding, unions, flex connectors, and sediment traps for gas distribution systems.
- Identify approved piping materials for interior gas distribution
- Explain the purpose and requirements of CSST bonding jumpers
- Describe proper pipe sizing based on length, fittings, pressure drop, and BTU load
- State the purpose and proper application of pipe thread sealant
- Explain the function of sediment traps, flex connectors, and unions
Leçon 1
Black Iron Pipe, CSST & Approved Materials
Approved Gas Piping Materials
The type of pipe commonly used for natural gas distribution inside buildings is black iron pipe or CSST (Corrugated Stainless Steel Tubing). These are the two primary materials approved for interior gas piping in Canadian installations.
Black iron pipe (also called black steel pipe) has been the traditional standard for gas piping for decades. It is strong, durable, and resistant to the corrosive effects of natural gas and propane. Black iron pipe uses threaded fittings and is joined with pipe thread sealant. It is available in standard sizes from 1/2 inch to 4 inches and larger.
CSST (Corrugated Stainless Steel Tubing) is a flexible, yellow-jacketed piping system that has become increasingly popular since the 1990s. CSST is faster to install than black iron pipe because it can be routed through walls and floors with fewer fittings. However, CSST requires special fittings and has unique installation requirements.
Black Iron Pipe
Joining: Threaded fittings with sealant
Flexibility: Rigid - requires elbows for turns
Installation: Slower, more fittings needed
Cost: Lower material cost
CSST
Joining: Proprietary compression fittings
Flexibility: Flexible - routes through cavities
Installation: Faster, fewer fittings
Cost: Higher material cost
Press-Connect Fittings
Certified press-connect fittings are now permitted under CSA B149.1:25 for gas piping systems up to NPS 4 (nominal pipe size 4 inches). Press-connect fittings use a mechanical pressing tool to cold-form a leak-tight joint on steel or other approved pipe without threading, welding, or solvents. The fittings must be specifically certified for gas service - press-connect fittings approved only for water or other services are not permitted on gas lines.
Press-Connect Fittings - Exam Point
CSA B149.1:25 permits certified press-connect fittings for gas piping up to NPS 4. The fittings must be listed and certified for gas service. This is a newer installation method that reduces threading work on larger commercial and industrial piping runs.
Materials NOT Permitted
Certain pipe materials are specifically prohibited for gas piping. PVC pipe, ABS pipe, and standard copper water pipe are not approved for interior gas piping in most Canadian jurisdictions. While some specialty copper tubing may be approved for certain gas applications in some areas, standard water-type copper pipe is not permitted.
CSST Bonding Requirements
CSST must have a bonding jumper installed to protect against lightning-induced surges. Lightning strikes near a building can induce electrical current in the CSST, potentially burning holes through the thin stainless steel wall. The bonding jumper connects the CSST system to the building's electrical grounding system, providing a safe path for this energy.
CSST Bonding Is Mandatory
A bonding jumper on CSST protects against lightning-induced surges. Failure to properly bond CSST has caused house fires. The bonding conductor must be sized per code and connected directly to the building grounding electrode system.
Black iron pipe and CSST are the approved materials for interior gas distribution. CSST requires a bonding jumper to protect against lightning damage. PVC, ABS, and standard copper water pipe are not approved for gas piping.