Piping, Tubing, and Fittings Installation

Installation of Pipes, Tubing, and Fittings

Chapter Introduction

This chapter covers the installation of pipes, tubing, and fittings for gas systems in Canada, in accordance with the Canadian Natural Gas and Propane Installation Code (CSA B149.1). This code is the mandatory national reference for all gas installers. As a Red Seal exam candidate, you must master the requirements for sizing, approved materials, assembly techniques, leak testing, and installation tolerances. This chapter is structured to cover each exam competency area with practical examples and common pitfalls.

Piping Materials: Requirements and Restrictions

Steel Pipe (Black or Galvanized)

Black steel is the most common material for natural gas and propane installations. Galvanized steel is prohibited for gas transmission, except for buried exterior piping protected against corrosion (CSA B149.1, Article 4.3.2). The reason: zinc coatings can flake off and clog burner orifices.

Key Requirements:

Steel must conform to ASTM A53 (Grade B) or ASTM A106.

Minimum wall thickness must be Schedule 40 for pipes with a nominal diameter ≤ 2 inches (DN 50). For larger diameters, Schedule 40 is also required unless pressure calculations justify otherwise.

Threads must conform to ASME B1.20.1 (NPT – National Pipe Thread). The number of visible threads after assembly must be 2 to 3 threads maximum.

Maximum Allowable Pressure Table (excerpt from CSA B149.1, Table 4.1):

Material	Maximum Pressure (kPa)	Maximum Temperature (°C)
Black steel Schedule 40	860	65
Black steel Schedule 80	1,720	65
Copper Type K or L	860	65
Polyethylene (PE)	700	38

Copper Tubing

Copper is permitted for natural gas and propane, but with significant restrictions:

Copper must be Type K or L (heavy or medium wall). Type M is prohibited.

Fittings must be brazed with a high-silver-content alloy (minimum 15% silver, melting point > 540°C). Soft solder (tin-lead) is strictly prohibited.

Copper cannot be used for propane gas if the pressure exceeds 860 kPa or if the gas contains free sulfur (CSA B149.1, Article 4.4.2).

Copper is prohibited for piping buried directly in the ground unless enclosed in a continuous protective sleeve.

Polyethylene (PE) Pipe

PE is used for buried piping only. It cannot be installed inside a building.

Requirements:

Conforms to CSA B137.4.

Yellow or black marking with yellow stripes.

Joined by thermal fusion (butt fusion or electrofusion) or by certified mechanical fittings.

Maximum pressure is 700 kPa for natural gas and 700 kPa for propane (vapor).

PE cannot be used for liquid propane (liquid phase).

Corrugated Stainless Steel Tubing (CSST)

Corrugated stainless steel tubing (known commercially as "TracPipe" or "Gastite") is permitted under CSA B149.1, Article 4.8. It must be certified to CSA 6.26 (or UL 2512). Its installation must follow the manufacturer's instructions, including:

Electrical grounding: CSST must be bonded in accordance with the Canadian Electrical Code, Part I (Rule 10-204). The bonding clamp must be installed on the gas inlet fitting, not on the tubing itself.

The minimum bend radius is 8 times the outside diameter of the tubing.

The tubing must be protected against mechanical damage (when passing through joists, wall penetrations).

Sizing of Piping Systems

Basic Principles

Sizing involves determining the inside diameter of each piping section so that the pressure at the point of use is sufficient. The CSA B149.1 code provides sizing tables (Annex A) based on:

Total equivalent length (actual length + equivalent length of fittings).

Required flow rate (m³/h or ft³/h).

Supply pressure.

Allowable pressure drop (generally 0.5 in. water column for low-pressure systems).

Pressure Drop Formula (approximation for natural gas, low pressure):

ΔP = 0.0005 × L × Q² / D⁵

Where:

ΔP = pressure drop (kPa)

L = equivalent length (m)

Q = flow rate (m³/h)

D = inside diameter (mm)

Note: This formula is an approximation. For the exam, use the tables in the code.

Equivalent Length of Fittings

Each fitting (elbow, tee, valve) adds resistance equivalent to a certain length of straight pipe. The following table gives typical equivalent lengths for a 25 mm (1 in.) steel pipe:

Fitting	Equivalent Length (m)
90° elbow (standard)	0.6
45° elbow	0.3
Tee (straight run)	0.3
Tee (branch)	1.2
Ball valve	0.3
Check valve	1.5

Rule of thumb: For each section, add the actual length and all equivalent lengths of fittings. Use this value in the sizing table.

Calculation Example

Problem: A system supplies two appliances: a water heater (flow rate 1.5 m³/h) and a range (flow rate 1.0 m³/h). The supply pressure is 7 in. water column (1.74 kPa). The total pipe length from the meter is 15 m, with 4 – 90° elbows and 1 valve. Determine the minimum diameter of the main section.

Solution:

56.Total flow rate = 1.5 + 1.0 = 2.5 m³/h.

57.Equivalent length = 15 m + (4 × 0.6 m) + 0.3 m = 15 + 2.4 + 0.3 = 17.7 m.

58.Consult the CSA B149.1 table (Annex A, Table A.1) for 2.5 m³/h and 18 m of length.

59.Result: minimum diameter = 19 mm (3/4 in.).

Exam Trap: Don't forget to include the equivalent lengths of fittings. Candidates who use only the actual length will undersize the pipe.

Assembly Techniques

Threading Steel Pipe

Threading must be done with a die conforming to ASME B1.20.1. Requirements:

Cut the pipe at a right angle (90°).

Deburr the inside and outside after cutting.

Apply a sealing compound (joint paste or PTFE tape) on the male threads only. Do not apply on female threads.

PTFE tape must be wrapped in the direction of the threads (clockwise) with a 50% overlap.

Tighten the fitting with a chain wrench or pipe wrench. Do not overtighten: 2 to 3 visible threads after assembly.

Prohibited: Using paint, putty, or hemp as a sealing product. Only products certified for gas are permitted.

Brazing Copper

Brazing copper for gas requires:

Cleaning surfaces with an abrasive (sandpaper or steel wool).

Applying an appropriate flux (high-temperature brazing flux).

Uniform heating with an oxyacetylene or oxypropane torch.

Inserting the filler metal (silver alloy ≥ 15%) as soon as the flux becomes liquid and transparent.

Natural cooling (do not quench in water).

Common Error: Using soft solder (tin) for gas fittings. This is prohibited and causes leaks.

Polyethylene Fusion

Butt fusion is the most common method for PE gas piping. Critical parameters:

Heating plate temperature: 200 to 230°C.

Fusion pressure: per manufacturer specifications.

Cooling time: minimum 10 minutes before handling.

Quality Control: The fusion bead must be uniform around the entire circumference. An irregular bead indicates poor alignment or incorrect temperature.

Appliance Connections

Appliance Connectors (Flexible)

Movable appliances (ranges, dryers) may be connected with metallic flexible connectors certified to CSA 6.16 (or ANSI Z21.24). Requirements:

Maximum length: 1.5 m (unless the manufacturer specifies otherwise).

The connector must not pass through a wall, floor, or ceiling.

The connector must be installed so it is not subject to mechanical stress.

A quick-disconnect fitting is permitted if certified.

Location of Shut-off Valves

Each appliance must have an individual shut-off valve that is accessible, installed within 1.8 m of the appliance (CSA B149.1, Article 6.6.1). The valve must be a ball valve or needle valve type, with a lever or handle clearly indicating the open/closed position.

Supports and Anchors

Piping must be supported at regular intervals to prevent stress and vibration. The following table gives maximum spacing for steel:

Nominal Diameter (in.)	Maximum Spacing (m)
1/2	1.8
3/4	2.1
1	2.4
1-1/4	2.7
1-1/2	3.0
2	3.4
3	4.0
4	4.6

Rule: Supports must be metal (galvanized or stainless steel). Plastic supports are prohibited for steel pipes.

Leak Testing

Test Pressure

Before commissioning, every installation must undergo a leak test. Requirements per CSA B149.1, Article 7.2:

Type of Installation	Test Pressure (kPa)	Minimum Duration
Low pressure (< 7 in. WC)	14 (2 psi)	15 minutes
High pressure (> 7 in. WC)	1.5 × maximum service pressure	30 minutes
Buried PE piping	700 kPa or 1.5 × service pressure (whichever is greater)	1 hour

Important: The test pressure must be measured with a calibrated gauge (accuracy ± 1%). The gauge must be installed at the lowest point of the system.

Test Procedure

106.Close all shut-off valves and cap open ends.

107.Fill the system with compressed air or inert gas (nitrogen).

108.Increase the pressure gradually to the test value.

109.Wait the minimum duration (15 minutes for low pressure).

110.Verify there is no pressure drop. A drop of 0.1 kPa or more indicates a leak.

111.Locate leaks with a soap solution (never with a flame).

Exam Trap: The test must be performed before installing the appliances. Appliances must not be subjected to the test pressure.

System Purging

After a successful test, the system must be purged to remove air. Purging is done with the service gas (natural gas or propane). The procedure:

115.Open the main valve slowly.

116.Purge each branch by opening appliance valves one at a time.

117.Verify the absence of air with a gas detector or by observing the flame of a pilot light.

Prohibited: Purging gas inside the building. Purging must be done outdoors or through a vent.

Safety Rules and Code Requirements

Room Ventilation

Gas appliances must be installed in adequately ventilated rooms. CSA B149.1 requires:

An air supply opening of at least 0.35 cm² per kW of total appliance input (for enclosed rooms).

An air exhaust opening of at least 0.18 cm² per kW.

Openings must communicate with the outdoors or with an adjacent unenclosed space.

Gas Detectors

Propane is heavier than air (density 1.5). In the event of a leak, it accumulates at floor level. Natural gas is lighter than air (density 0.6) and accumulates at ceiling level. Detectors must be installed:

For propane: 30 cm from the floor.

For natural gas: 30 cm from the ceiling.

Grounding and Bonding

All gas piping must be grounded in accordance with the Canadian Electrical Code, Part I. The bonding connection must be installed:

At the building entrance (customer side of the meter).

With a copper conductor of minimum size 6 AWG (10 mm²).

The ground resistance must be ≤ 25 Ω.

Caution: CSST (flexible tubing) is particularly susceptible to damage from lightning. The bond must be installed on the inlet fitting, not on the tubing.

Pitfalls to Avoid

138.Using galvanized steel for gas: prohibited except in specific cases (protected buried piping).

139.Soldering copper fittings with lead: soft solder is prohibited; silver brazing is mandatory.

140.Forgetting equivalent lengths of fittings in sizing: undersizing and excessive pressure drop.

141.Installing a 3 m flexible connector for a range: the maximum length is 1.5 m.

142.Performing the leak test with appliances connected: appliances must be isolated.

143.Using a flame to detect leaks: always use a soap solution or electronic detector.

144.Not bonding CSST: risk of electric shock and non-compliance with the Canadian Electrical Code.

145.Installing a shut-off valve more than 1.8 m from the appliance: non-compliant with CSA B149.1.

146.Using PE for an indoor installation: PE is reserved for buried piping.

147.Purging gas indoors: purging must be done outdoors.

Summary

Approved materials are black steel (Schedule 40 minimum), copper Type K/L (silver-brazed), PE (buried only), and CSST (with bonding).

Sizing uses the tables in Annex A of CSA B149.1, accounting for total equivalent length (actual length + equivalent lengths of fittings).

Leak tests require a pressure of 14 kPa (low pressure) or 1.5 × service pressure (high pressure), with a minimum duration of 15 or 30 minutes.

Individual shut-off valves must be accessible and within 1.8 m of each appliance.

Room ventilation is mandatory: 0.35 cm²/kW for air supply.

Grounding and bonding are mandatory for all piping, with a minimum conductor of 6 AWG.

CSST must be bonded on the inlet fitting, never on the tubing itself.

System purging is done outdoors, never inside the building.

Exam Tips

Memorize key values: test pressure (14 kPa), maximum flexible connector length (1.5 m), valve distance (1.8 m), support spacing (table above).

Practice sizing calculations with the code tables. The exam typically contains 2 to 3 sizing questions.

Know the differences between natural gas and propane: density, service pressure, detector placement.

Review Articles 4.1 to 4.8 of CSA B149.1 (materials) and 6.1 to 6.10 (appliance installation). These articles are the basis for 70% of the questions in this chapter.

Use the manometer: leak test questions often include pressure drop calculations. The formula ΔP = 0.0005 × L × Q² / D⁵ is useful for theoretical questions.

Normative References

CSA B149.1: Canadian Natural Gas and Propane Installation Code.

CSA B137.4: Polyethylene piping systems for gas.

CSA 6.26: Corrugated stainless steel tubing for gas.

CSA 6.16: Metallic flexible connectors for appliance connection.

ASME B1.20.1: Pipe threads (NPT).

Canadian Electrical Code, Part I: Grounding and bonding rules.

End of Chapter 3. Proceed to the next chapter: "Gas Appliances and Ventilation" to complete your Red Seal exam preparation.