BENSON OLYMPIC WH - Flue System

46 pages

Save Page as PDF

To Next Page

To Next Page

To Previous Page

To Previous Page

Loading...

2.6 Flue

system

Warning

It is

essential

that

the

products

of

combustion

are

flued to the

outside

of

the

building.

Each

heater

must

have

its

own

separate

flue,

with

a flue

diameter

of

not

less

than

is

detailed

in section

8.1

within

this

manual.

The

minimum

vertical

length

of

flue

must

not

be

less

than

3m.

The

flue

should

rise

vertically,

and

the

number

of

bends

should

be

kept

to

a

minimum.

It

is

strongly

advised

that

BS

5854; 1980,

and

BS

5440;

parts

1

and

2,

are

used

as

consultative

documents

wh

en

considering

flue requirements.

Care

should

be

taken

to

ensure

that

the flue

terminal

is

not

situated

in a

high

pressure

area,

the

proximity

of

buildings

and

other

obstacles

which

will influence this

must

be

taken

into

account,

preferably

at

the

design

stage. See figures 2 - 12.

Provision

must

be

made

for

the

disconnection

of

the

flue

for

inspection

and

service

requirements,

and

it is

strongly

advised

that

where

bends

are fitted inspection covers

are

included.

The

materials

from

which

the

flue is

constructed

must

be

non-combustible, resistant to

internal

and

external corrosion,

and

be

capable

of

withstanding

the stresses

and

loadings

associated

with

normal

use.

When

designing

the

flue

system

the

prevention

of

the

formation

and

entrapment

of

condensation

must

be

a key

consideration.

Twin

wall

or

insulated

systems

are

recommended

as

they tend

to inhibit the

formation

of

condensates.

Where

condensation

is

unavoidable

traps

should

be

included

to

encourage

the

condensates

to

flow

freely to a

point

from

"vhich

they

may

be

released,

prederably

into

a gully.

The

condensate

pipe

from the flue to the

disposal

point

must

be

made

from corrosion resistant

pipe

of

not

less

than

25mm

internal

diameter.

If

the flue passes

through

a "vall, ceiling,

or

roof

made

from

combustible

material

then

it has to

be

sleeved

so

as to

provide

a

minimum

of a

25mm

void

between

the exterior of

the

flue

and

the

internal

waU

of

the

sleeve.

The

maximum

permitted

temperature

of

any

adjacent

combustible

material

is 65°C.

The

position

of

the flue

and

its

terminal

should

be

such

that

it

does

not

impair

the

combustion

process.

It

should

terminate

in

an

exposed

position

so

as to

allow

the

escape

and

dissipation

of the

flue gases

without

risk

of

their

re-entering

the

property

through

windows,

ventilation ports, etc.

The

flue

should

extend

to

at

least

1m

above

the

height

of

any

object

within

3.5m of the terminal.

Flue

terminals

should

be

fitted

on

all flues

with

a

diameter

of

200mm

or

less. The

terminal

must

be

of

the

approved

type,

and

have

outlet

grilles

on

all

sides

giving

a total free

area

of

at

least

double

that

of

the flue.

Caution

It

is

imperative

that

the flue

should

be

properly

sealed

where

it

passes

through

the roof, this

can

best

be

achieved

by

using

the

approved

method

of

roof flashing plate

and

cravat.

Note

It

should

be

noted

that

claims

made

under

warranty

and

attributed

to the ingress

of

water

may

not

be

considered

especially if

an

approved

method

of

sealing

has

not

been

used,

or

if the

design

of

the

flue

has

not

made

provision

for possible

condensation

problems.

11

Table of Contents