PIPING EXPANSION,

SUPPORT, & INSULATION5th Class Power Engineering Book 1 Unit 5,

Chapter 16

Learning Outcome

Discuss piping expansion, support and insulation

Learning Objective 1

Explain pipe expansion and the principle of

expansion bends and joints

Piping Expansion

Pipeline will expand and contract with change in

temperature

Linear Expansion Example

10 metre steam pipe heated from ambient

temperature (20 C) to temperature of 15 psi steam

(121 C)

Original length x linear expansion constant x change

in temperature

= 10 m x 13 x 10-6 x 101 = 13.13 mm

Expansion Bend

Expansion Bend

High pressures steam

No maintenance

Small risk of leak

Space required

Initial cost of pipe

Ongoing operational cost due to pressure

drop/frictional losses though the additional pipe

and fittings

Expansion Joints

Slip Expansion Joints

Corrugated Bellows Expansion Joints

Slip Expansion Joints

Slip Expansion Joint

Low and medium pressures

Require maintenance—packing

Less space than expansion bends

Expansion Joint

Tunnel

Corrugated Bellows Joints

https://www.youtube.com/watch?v=PWbAgVjrO4

U

Minute 1.24 – 1.26

Learning Objective 2

Explain the purpose of pipe supports and describe

various pipe support designs

Piping Codes

Section 121

Section 921

Pipe Support

Protect equipment from weight of piping

Protect pipe from stress of sagging

Provide means to allow for free movement of

thermal expansion/contraction

Hangers for pipe over NPS 2 ½” must be

adjustable while pipe is in service

Hangers

Roller Stand

Anchors

Constant Support

Objective 3

Explain the purposes for pipe insulation and

describe the use of common insulation materials

Purposes of Pipe Insulation

Reduce heat loss from steam, feedwater,

refrigeration piping

Plant efficiency—deliver energy to end use

Control piping surface corrosion “pipe sweat”

Safety and health of plant personnel

Working at elevated temperatures

Contact burns

Fire Protection

Good Insulation

High insulating value

Long life

Vermin proof

Non-corrosive

Retains shape/insulating value when wet

Ease of installation

Safe to health

Insulation

Transfers heat poorly

Many tiny air pockets

interrupt convention currents

Interrupt conduction pathways

Coefficient of thermal conductivity

Measure of the amount of energy that will be

transmitted through a material

Joules/second/1 sq metre area/1 metre thickness/1 degree

temp difference

Watts/metre Kelvin

Low number, better insulator

Molded Insulation

Finishing