Anvil International, Piping & Pipe Hanger Design and Engineering 5www.anvilintl.com

H-4

H-5

BGate

Valve

H-6

H-8

H-3

5'-0"

15'-0"

7'-0"

2'-0"

5'-0"

10'-0"

40'-0"

5'-0"

5'-0"

5'-0"

2'-0"

2'-0"

3'-0"

8'-0"

5'-0"

12" Pipe5'-0"

5'-0"

1'-0"11'-0"

2'-0"

3'-0"

A

4'-0"

H-2

H-1

Check

Valve 6'-0"

H-7

6" Pipe

4'-0"

5'-0"

3'-6"

12'-0"

12'-0"

4'-0"

To SuitH-9

C

GateValve

45°

three fourths the suggested maximum span shown in the table

on the previous page.

In considering the vertical section of the pipe on which H-3 and

H-4 are shown, it should first be noted that this section of the

pipe could be supported by one hanger rather than two as

indicated. Two hangers will certainly provide greater stability

than will a single hanger. Another deciding factor as to whether

one hanger or a multiple hangers should be used is the

strength of the supporting steel members of the structure. The

use of two hangers will permit the total riser weight to be

proportioned to two elevations of the structure, avoiding the

concentration of all the riser load at one building elevation.

The locations for hangers H-5 and H-6 are governed by the

suggested maximum span as well as the position of the

concentrated valve weight. Consequently, H-6 has been

located adjacent to the valve, and H-5 at a convenient location

between the valve and the 12 inch riser.

The location of hanger H-7 will be determined by calculation to

satisfy the condition that no pipe load is to be applied to

terminal connection C. It is obvious that by moving the hanger

along the 12 foot section of pipe, the amount of load on

connection C will vary. One support location exists where the

entire section will be "balanced", and the load at C equal to

zero.

The calculations to determine the exact location of H-7 are

shown in the section entitled "Hanger Load Calculation".

NOTE:

Allowable load at connection A is 500 lbs.

Allowable load at connection B and C is zero.

All bends are 5 diameter bends.

All elbows are L.R. Ells.

Operating temperature is 1,050°F.

All pipe is Sch. 160 A 335 P12.

FIGURE 1 – SAMPLE PROBLEM

The spans in table are in accordance with MSS Standard

Practice SP-69. They do not apply where concentrated

weights such as valves or heavy fittings or where changes in

direction of the piping system occur between hangers.

For concentrated loads, supports should be placed as close

as possible to the load in order to minimize bending stresses.

Where changes in direction of the piping of any critical system

occur between hangers; it is considered good practice to keep

the total length of pipe between the supports less than 3⁄4 the

full spans in table below.

When practical, a hanger should be located immediately

adjacent to any change in direction of the piping.

SAMPLE PROBLEM

In the sample problem (Figure 1) seven supports are shown on

the 12 inch line, and two on the 6 inch pipe.

Note that the hanger H-1 has been placed adjacent to the

valve weight concentration. The proximity of the hanger to the

valve is helpful in keeping the load at terminal connection A to

a minimum. Also, the bending stresses induced in the pipe by

the valve weight are kept to a minimum.

The selection of the location for hanger H-2 entails a change in

direction of the pipe between two hangers. In order to avoid

excessive overhang of the pipe between hangers H-1 and H-2,

the length of pipe between these hangers is made less than

THE DESIGN OF PIPE HANGERS