What you are likely to find
A Fullerton house built in the 1950s, 60s or 70s was almost always piped in black iron: dark, threaded steel pipe joined with screwed fittings. On a slab-on-grade tract home it usually runs from the meter up an exterior wall and through the attic, dropping down to the furnace, water heater, range and dryer.
Later remodels and appliance additions often brought in yellow-jacketed flexible tubing called CSST. Lines buried across the yard to a barbecue or pool heater are commonly plastic pipe made for gas. Many houses now have a mix of all three, joined at transition fittings.
The three common materials
| Material | Where it is used | Strengths | Watch for |
|---|---|---|---|
| Black iron (steel) | Exposed and concealed indoor runs, risers, older homes | Rigid, durable, familiar to every inspector | Rust at exterior walls and where it meets soil; threaded joints that loosen |
| CSST (yellow corrugated stainless) | Newer indoor runs, attic and wall routing, additions | Fewer joints, easy to route through framing | Needs maker-specific fittings and proper bonding; damage from nails or screws |
| Polyethylene (plastic gas pipe) | Buried outdoor lines | Does not rust underground | Must be buried and transition to metal before coming above ground; dig damage |
| Flexible appliance connector | Last short link to an appliance | Lets the appliance move | Kinks, reuse, older uncoated brass types |
Repairing iron vs. rerouting in CSST
When an old iron run needs work, the choice is often between replacing it like for like or rerouting part of it in CSST.
Like-for-like black iron
- Matches the existing system
- Each new joint is a threaded fitting that has to be sealed and tested
- Heavy and slow to route in a tight attic
- No special bonding beyond normal practice
Rerouting in CSST
- Long runs with few joints
- Fits through framing where rigid pipe would not
- Must be installed by someone trained on that product
- Bonding and protection plates required per the maker's instructions
Terms you may hear
- Riser
- The pipe that comes up out of the ground to the meter. On the utility side it belongs to SoCalGas.
- House line
- The piping from the meter outlet into and through the house.
- Transition fitting
- A fitting that joins one material to another, such as buried plastic to above-ground metal.
- Sediment trap
- A short capped leg at an appliance inlet that catches debris before it reaches the controls, installed where code requires it.
- Bonding
- Connecting gas piping to the home's electrical grounding system so stray electrical current has a safe path.
Questions to ask about materials
- What is my existing gas piping made of, and where does it run?
- Why do you recommend this material for the repair or extension?
- If you are using CSST, are you trained on that brand, and how will it be bonded?
- Where will buried plastic pipe transition to metal?
- Will the job need a permit and inspection?
Common questions
Is black iron gas pipe outdated?
No. It is still widely used. Older runs mainly need attention where they have rusted, loosened or been modified over the years.
Is yellow CSST safe?
It is a common, accepted material when installed and bonded according to the maker's instructions and local code.
Can copper be used for gas?
Rules on copper for gas vary. Check with the city building division and your contractor rather than assuming.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.