CEA 4001 - Annex G Methods for sizing pipework; Calculation of pressure losses in pipework

190 pages

Save Page as PDF

To Next Page

To Next Page

To Previous Page

To Previous Page

Loading...

132

Annex G

Methods for sizing pipework

G.1 Calculation of pressure losses in pipework

G.1.1 Pipe friction loss

Frictional

pressure

loss

in

pipes

shall

be

hydraulically

calculated.

The

Hazen-Williams

formula

should

be

used:

6,05

x10

5

p =

_____

L

Q

1,85

C

1,85

x

d

4,87

where:

p

is

the

pressure

loss

in

the

pipe,

in

bar;

Q

is

the

flow

through

the

pipe,

in

litres

per

minute;

d

is

the

mean

internal

diameter

of

the

pipe,

in

millimetres;

C

is

a

constant

for

the

type

and

condition

of

the

pipe

(see

Table

G1);

L

is

the

equivalent

length

of

pipe

and

fittings,

in

metres.

The

values

of

C

to

be

used

in

sprinkler

installation

and

water

supply

calculations

shall

be

as

indicated

in

table

G1.

Table 37: C values for various types of pipe (G1)

Type

of

pipe

Value

of

C

cast

iron

ductile

iron

mild

steel

galvanised

steel

spun

cement

stainless

steel

reinforced

glass

fibre

100

110

120

120

130

140

140

The

pressure

loss

due

to

velocity

may

be

ignored.

G.1.2 Static pressure difference

The

static

pressure

difference

between

two

inter-connecting

points

in

a

system

shall

be

calculated

from:

Table of Contents