2.1 Hand Tools for Gas Piping and Mechanical Assembly

Hand Tools for Gas Piping and Mechanical Assembly

Under Ontario Regulation 215/01 and the CSA B149.1 Natural Gas and Propane Installation Code, a Gas Technician 3 (G3) must assemble gas piping and tubing systems that remain permanently gastight. Selecting the proper trade hand tools and applying correct mechanical techniques prevents leaks, component damage, and catastrophic gas hazards.

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1. Pipe Wrenches: Mechanics, Direction of Force & Sizing

The straight pipe wrench (Stillson pattern) is designed to grip unmachined cylindrical steel pipe, such as Schedule 40 black iron.

Anatomy and Camming Action

A pipe wrench comprises four core parts:

• Heel Jaw: A hardened steel, serrated jaw permanently pinned into the handle housing.
• Hook Jaw: A floating forged-steel upper jaw that pivots within the housing frame.
• Knurled Nut: An adjustment ring that sets jaw opening capacity.
• Spring Mechanism: Internal leaf springs that allow the hook jaw to float and tilt under load.

The tool operates via a mechanical camming wedge action. As torque is applied, the floating hook jaw tilts inward toward the fixed heel jaw, driving the serrated teeth deeper into the pipe circumference.

Direction of Force: The Open Throat Rule

Force must always be pulled toward the open throat of the hook jaw. Pulling toward the throat forces the floating jaw inward, increasing bite as torque rises.

Conversely, pushing a pipe wrench away from the open throat is dangerous. Pushing causes the hook jaw to pivot outward, releasing its grip. The teeth slip across the metal, rounding the pipe fitting, stripping jaw teeth, and risking severe hand and knuckle injuries. Furthermore, pushing places severe cantilever stress on the hook jaw shank, which can snap the forged steel.

Sizing Guidelines

• Offset and End Wrenches: Feature angled jaws parallel to the handle to access tight corners or overhead pipe banks.
• Aluminum Wrenches: Provide equivalent structural strength to ductile iron while reducing tool weight by approximately $40\%$, reducing fatigue during overhead work.

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2. The Two-Wrench Technique ("Holding Back")

Whenever assembling or servicing threaded gas piping, applying torque with a single wrench transmits torsional stress upstream. The two-wrench technique (using a "hold-back wrench") is mandatory on all gas connections.

1. Backing Wrench (Hold-Back): Placed on the stationary fitting, coupling, or gas valve body, oriented to oppose the tightening wrench.
2. Tightening Wrench: Placed on the pipe nipple or component being rotated.

Hazards of Failing to Hold Back

• Disturbed Upstream Joints: Torsional stress breaks the seal of concealed joints behind walls or in joist spaces, causing undetected leaks.
• Cracked Gas Valves: Appliance control valves (furnaces, water heaters) feature cast aluminum or brass housings. Unopposed torque warps internal valve seats, damages shut-off solenoids, or cracks the valve casting.
• Sheared Internal Lines: Rotational twisting breaks internal copper pilot lines or burner connections inside appliances.

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3. Tubing Cutters, Reaming & Deburring Mechanics

Copper tubing (Types G, L, or K approved under CSA B149.1) and Corrugated Stainless Steel Tubing (CSST) require specialized cutting tools to maintain circular integrity.

Tubing Cutters

A tubing cutter features a hardened alloy cutting wheel opposed by guide rollers and an adjustable feed screw.

• Tighten the feed knob until the wheel contacts the tube, rotate one full revolution ($360^\circ$) to set a tracking line, then advance the knob $1/4$ to $1/2$ turn per revolution.
• Never over-tighten the feed knob. Forcing the wheel flattens the tubing out-of-round (ovality), work-hardens copper, and forces an excessive internal burr into the bore.
• Use manufacturer-specified stainless steel cutter wheels for CSST to avoid tearing corrugations.

Mandatory Reaming

Cutting pipe or tubing forces metal inward, creating a sharp internal burr. CSA B149.1 Clause 6.8 (piping practices) requires cutting burrs to be removed, so every cut pipe and tubing end is reamed:

1. Flow Restriction: An unreamed burr narrows the bore, causing turbulence and added pressure drop ($\Delta P$) that can starve appliances at peak firing.
2. Debris Accumulation: Burrs trap circulating pipe scale, rust, and thread sealant, eventually clogging appliance orifices and pilot burners.
3. Flare Failure: Burrs cause stress risers that crack copper flare skirts during expansion.

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4. Flaring Tools: 45° SAE vs. 37° JIC Standards

Flared connections are a common joint for annealed copper tubing (see the joint requirements in CSA B149.1 Clause 6.9). Flared joints rely on a metal-to-metal seal between a brass fitting nose and an expanded copper tube end.

The 45° SAE Standard

• $45^\circ\text{ SAE}$ (SAE J513): Mandatory for fuel gas and HVAC/R installations across North America.
• $37^\circ\text{ JIC}$ (SAE J514): Reserved for hydraulic, military, and aircraft fluid lines.
• Incompatibility: Mating a $45^\circ$ flare with a $37^\circ$ fitting creates a point-contact line seal that fails under gas pressure. Gas technicians must verify that flaring blocks are stamped $45^\circ\text{ SAE}$.

Flaring Procedure

1. Slide the flare nut onto the tubing with the threads facing the cut end before clamping.
2. Clamp tubing in the flaring block with the tube extending approximately the thickness of a dime or nickel ($\approx 1/16\text{ inch}$ or $1.5\text{ mm}$) above the block face.
3. Use an eccentric (orbital) flaring tool, which rolls off-center to burnish the copper evenly without thinning or work-hardening the skirt.
4. Inspect the finished flare: it must be smooth, concentric, and free of cracks, splits, or galling.

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5. Lever Tubing Benders and Pipe Vises

• Lever Tubing Benders: Feature calibrated degree marks ($0^\circ, 45^\circ, 90^\circ, 180^\circ$) on a fixed forming shoe. Bending in one smooth stroke preserves cross-sectional circularity and prevents kinking or flattening. Reversing an over-bent tube work-hardens copper, causing stress cracks.
• Pipe Vises: Portable tristands provide rigid field support. Yoke vises use a V-shaped screw jaw for rapid clamping of rigid pipe, while chain vises wrap high-tensile chain around the circumference, distributing pressure evenly to prevent crushing thin-wall pipe.

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Summary of Gas Piping Hand Tools