Install and Align Piping and Associated Systems

Installing and Aligning Piping and Related Systems

Module Introduction

This chapter covers the installation, alignment, and commissioning of piping systems associated with boilers and pressure vessels. As a journeyperson boilermaker, you will be called upon to install feedwater piping, steam lines, blowdown systems, gas lines, and hydraulic circuits. The Red Seal exam assesses your ability to interpret drawings, apply alignment tolerances, perform thermal expansion calculations, and comply with applicable Canadian standards. This chapter prepares you specifically for these requirements.

1. Boilermaker Roles and Responsibilities in Piping

The boilermaker does not install piping the same way a plumber or pipefitter does. Your work focuses on systems directly connected to the boiler and pressure vessels. Your responsibilities include:

You must be able to read isometric drawings and piping drawings, identify standardized symbols, and understand material specifications.

2. Applicable Canadian Standards and Codes

2.1 Canadian Electrical Code, Chapter V

Although this code primarily concerns electricity, it applies to piping systems when they carry flammable fluids or gases. Rule 8-200 of the Canadian Electrical Code, Chapter V, addresses grounding and bonding requirements for piping carrying hazardous materials. You must ensure that piping sections are properly bonded together to prevent the accumulation of electrostatic charges.

2.2 CSA B51 – Boiler, Pressure Vessel, and Pressure Piping Code

CSA B51 is the primary reference for the installation of boilers and pressure piping in Canada. It covers:

This standard requires that all pressure piping be marked in accordance with CSA B51 requirements and be inspected before being placed into service.

2.3 CSA B149.1 – Natural Gas and Propane Installation Code

CSA B149.1 applies to the installation of natural gas and propane piping. Key points for the boilermaker:

2.4 ASME B31.1 – Power Piping

Although American in origin, ASME B31.1 is widely adopted in Canada for power plant and boiler piping. It specifies:

3. Piping Materials and Identification

3.1 Types of Materials

3.2 Pipe Marking

Each pipe must bear markings indicating:

Exam Trap: You will often be asked to select the correct material for a given application. Remember that carbon steel is the default choice for steam and hot water, unless corrosion or temperature rules it out.

4. Pipe Preparation and Cutting

4.1 Cutting Methods

4.2 Edge Preparation for Welding

Edges must be prepared according to the specified bevel (generally 37.5° ± 2.5°). The root face must measure between 1.5 mm and 2.5 mm for Schedule 40 pipes and heavier. The root gap between the two pieces must be 2 to 3 mm to allow for complete penetration.

4.3 Cleaning

Before welding or assembly, clean the inside and outside of the pipe over at least 25 mm on each side of the joint. Remove:

5. Piping Alignment

5.1 Alignment Tolerances

Alignment is critical to avoid excessive stress, leaks, and premature failure. Typical tolerances per ASME B31.1:

5.2 Measurement Methods

5.3 Flange Alignment

Flanges must be aligned so that:

Procedure:

5.4 Assembly Stresses

Never force a pipe to bring it to a flange. Excessive assembly stress causes:

If the gap exceeds tolerance, cut and readjust the pipe rather than forcing it.

6. Thermal Expansion and Compensators

6.1 Calculating Thermal Expansion

The linear expansion of a pipe is calculated using the formula:

ΔL = α × L × ΔT

Where:

Typical expansion coefficients:

Example: A 30 m carbon steel pipe carries steam at 200 °C. The ambient temperature is 20 °C. The expansion is:

ΔL = 0.0117 × 30 × (200 − 20) = 0.0117 × 30 × 180 = 63.2 mm

This expansion of more than 6 cm must be absorbed by compensators or expansion loops.

6.2 Types of Compensators

6.3 Compensator Installation Rules

7. Pipe Supports and Anchors

7.1 Types of Supports

7.2 Support Rules per CSA B149.1

For gas piping:

7.3 Anchor Points

Anchors must be placed:

A poorly positioned anchor can concentrate stresses and cause failure.

8. Fittings and Joints

8.1 Threaded Fittings

Used for small-diameter pipes (≤ DN 50) and low pressures. Rules:

8.2 Welded Fittings

Welding is the preferred method for high pressures and temperatures. Types of joints:

8.3 Flanged Fittings

Flanges are classified by their pressure class:

Flange bolt tightening procedure:

9. Pressure Testing and Commissioning

9.1 Hydrostatic Test

The hydrostatic test is mandatory before any pressure piping is placed into service. Requirements per CSA B51:

9.2 Pneumatic Test

Used when a hydrostatic test is impossible (weight of water, sensitive materials). More dangerous:

9.3 Test Procedure

9.4 Purging and Flushing

Before commissioning:

10. Boiler-Specific Systems

10.1 Feedwater Line

10.2 Main Steam Line

10.3 Blowdown Line

10.4 Condensate System

11. Safety During Installation

11.1 Specific Hazards

11.2 Personal Protective Equipment (PPE)

11.3 Work Permits

12. Reading Drawings and Symbols

12.1 Piping Symbols

12.2 Common Abbreviations

12.3 Reading Isometric Drawings

Isometric drawings represent piping in three dimensions on a flat surface. Rules:

13. Practical Calculations for the Exam

13.1 Wall Thickness Calculation

Per ASME B31.1, the minimum wall thickness is calculated:

t = (P × D) / (2 × (S × E + P × Y))

Where:

Example: Pressure of 10 MPa, outside diameter of 168 mm, allowable stress of 120 MPa, E = 1.0, Y = 0.4.

t = (10 × 168) / (2 × (120 × 1.0 + 10 × 0.4)) = 1680 / (2 × 124) = 1680 / 248 = 6.77 mm

Choose the schedule whose thickness is ≥ 6.77 mm (Sch 40 for DN 150 has a thickness of 7.11 mm).

13.2 Pressure Drop Calculation

The pressure drop in piping is calculated using the Darcy-Weisbach formula:

ΔP = f × (L/D) × (ρ × v² / 2)

Where:

13.3 Unit Conversions

14. Pitfalls to Avoid

15. Exam Tips

Summary

Pitfalls to Avoid

This chapter has prepared you to master the installation and alignment of piping according to Red Seal requirements. Review the formulas, tolerances, and standards. Good luck with your preparation!