Gas Line Extension Proposal Template
Professional plumbing scope for extending natural gas or propane piping to backup generators, pool heaters, gas ranges, and outdoor fire features.
Complete Scope of Work
Copy or customize these verbatim specifications into your contractor proposal.
1. Demand Calculation & Gas Sizing
BTU demand calculation and pipe sizing verification.
- Perform longest-length method pipe sizing calculation per IFGC Chapter 4 tables to guarantee adequate supply pressure.
- Verify existing gas meter regulator delivery pressure (typically 7-inch water column for low pressure, 2 PSI for medium pressure).
2. Gas Piping Installation
Pipe routing, hangers, and fittings.
- Install Schedule 40 black iron pipe or corrugated stainless steel tubing (CSST) with continuous bonding wire.
- Route piping through crawlspace, attic, or exterior trench with appropriate pipe supports and firestopping.
- Install underground high-density polyethylene (HDPE) gas pipe with anodeless transition risers for exterior yard runs.
3. Shutoff Valves, Regulators & Sediment Traps
Safety controls and appliance connections.
- Install full-port 600 WOG brass ball shutoff valve at each appliance branch connection.
- Install sediment trap (drip leg) upstream of appliance connection to collect debris and moisture.
- Install secondary line pressure regulator if system operates on 2 PSI delivery.
4. Pressure Testing, Inspection & Purging
Code pressure test and appliance startup.
- Pressurize new gas piping system to minimum 15 PSI (or 3x working pressure) for 15 minutes per municipal inspection standards.
- Perform bubble-leak test on all mechanical joints using certified gas leak detector fluid.
- Purge air from line, light pilot lights, and verify operational pressure at appliance burners.
- 2-Year contractor workmanship warranty.
Standard Line-Item Material Allowances
Clear material specifications that protect against ambiguous scope arguments.
| Component / Assembly | Standard Specification | Unit / Allowance |
|---|---|---|
| Schedule 40 Black Iron Pipe | 3/4-Inch to 1-1/4-Inch threaded pipe with malleable iron fittings | Linear Feet |
| Underground HDPE Gas Pipe | Yellow SDR-11 polyethylene gas pipe with tracer wire | Linear Feet |
| Anodeless Risers | Pre-bent steel-to-polyethylene service transition risers | Per Unit |
| Gas Ball Valves & Sediment Traps | CSA-approved gas shutoff valves with black iron nipples | Per Branch |
| CSST Bonding Clamp & Wire | #6 AWG bare copper bonding clamp to main electrical ground | 1 Assembly |
Scope-Gap Protections: 3 Clauses to Include
These contractual gotchas account for 85% of change-order arguments on gas line extension proposal templates.
The Risk: Connecting a 400,000 BTU pool heater or generator to a 1/2-inch branch starves existing home appliances.
Protective Clause: Specifies that pipe sizing was calculated from the main meter to appliance; main line upsizing from meter is included.
The Risk: Gas piping in yards must be buried at least 12 to 18 inches; hitting bedrock or roots increases hand labor.
Protective Clause: Specifies standard soft-dig trenching depth; hard rock excavation or concrete sawing is billed at an hourly rate.
The Risk: Yellow CSST flexible gas pipe requires direct bonding to the electrical service grounding electrode to prevent lightning puncture.
Protective Clause: Explicitly details installation of electrical bonding clamp and #6 copper ground wire per manufacturer installation instructions.
Governing Building Codes & Standards
Frequently Asked Questions
Can corrugated stainless steel tubing (CSST) be run underground in a yard?▾
No. CSST and black iron cannot be buried directly in soil. Exterior underground runs require specialized yellow polyethylene (HDPE) gas pipe with steel anodeless risers at each end where pipe exits the ground.
What is a sediment trap (drip leg) and why is it mandatory on gas lines?▾
A sediment trap is a vertical capped tee installed right before the appliance that uses gravity and directional change to catch metal shavings, pipe dope, and moisture before they enter delicate gas valves.
Related Plumbing Proposal Scopes
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