3.
General Requirements
3.1
Related Documents
The installation of the air heater(s) must be in accordance
with the rules in force and the relevant requirements of the
Gas Safety Regulations, Building Regulations and the I.E.E.
Regulations for Electrical Installations.
It should be in accordance also with any relevant requirements
of the local gas region, local authority and fire authority and
the relevant recommendations of the following documents.
British Gas Plc Publications
IM/11 : 1989 Flues for Commercial and Industrial Gas Fired
Boilers and Air Heaters
IM/16 : 1988 Guidance notes for the installation of gas
pipework, boosters and compressors in Customer’s premises
(excluding domestic installation of 25mm and below).
British Standards Code of Practice
BS 5588 Fire precautions in the design and construction of
buildings.
Part 2 : 1985 Code of Practice for Shops
Part 3 : 1983 Code of Practice for Office Buildings
BS 6230: 1991 Installation of Gas Fired Forced Convection
Air Heaters for Commercial and Industrial Space Heating.
Those appliances having an input rating not exceeding 60kW
viz. NCA-G 100 and NCA-G 150 must be installed in accordance
with the relevant recommendations of the following documents.
BS 5440 Flues and Air Supply for gas appliances of rated
input not exceeding 60kW (1st and 2nd family gases).
Part 1 - Flues, Part 2 - Air Supply
For NCA-G100 and NCA-G150 units reference should also be
made to BS 5864. Code of Practice for installation of gas-
fired ducted-air heaters of rated input not exceeding 60kW.
3.2
Location
The location chosen for the air heater must permit the
provision of a satisfactory flue system and an adequate air
supply. The location must also provide adequate space for
servicing and air circulation around the air heater.
The heater(s) must not be installed in conditions for which
it is not specifically designed e.g. where the atmospheric is
corrosive or salty and where high wind speeds may affect
burner operation, and they are not suitable for outdoor use.
Where the location of the air heater is such that it might
suffer external mechanical damage e.g. from overhead cranes,
fork lift trucks, it must be suitably protected.
NCA-G units are designed to operate in a maximum ambient
temperature of 25°C.
3.3
Gas Supply
3.3.1 Service Pipes
The local gas undertaking should be consulted at the
installation planning stage in order to establish the availability
of an adequate supply of gas. An existing service pipe must
not be used without prior consultation with the local gas
undertaking.
3.3.2 Meters
A gas meter is connected to the service pipe by the local gas
undertaking or a local gas undertaking contractor. An existing
meter should be checked, preferably by the gas undertaking,
to ensure that the meter is adequate to deal with the total
rate of gas supply required.
3.3.3. Installation Pipes
Installation pipes should be fitted in accordance with
IM/16:1988. Pipework from the meter to the air heater must
be of adequate size. Do not use pipes of a smaller size than
the inlet gas connection of the heater. The complete
installation must be tested for soundness as described in the
above Code. The complete installation must be tested for
soundness as described in BS 6230.
3.3.4. Boosted Supplies
Where it is necessary to employ a gas pressure booster the
controls must include a low pressure cut off switch at the
booster inlet. The local gas undertaking must be consulted
before a gas pressure booster is fitted.
3.4
Flue System
Detailed recommendations for fluing are given in BS 5440,
Part 1 (Flues) and IM/11.
The air heater must be connected to a closed flue system.
The cross sectional area of the flue serving the appliance
must be not less than the area of the flue outlet to the air
heater.
Materials used for the flue system should be mechanically
robust, resistant to internal and external corrosion,
noncombustible and durable under the conditions to which
they are likely to be subjected.
Prevention of condensation within the flue should be an
important factor in the design of the flue system. In order
to minimise condensation the use of double walled flue pipe
or insulation is recommended. If double walled flue pipe is
used it should be of an acceptable type.
Where condensation in the flue is unavoidable provision
should be made for condensation to flow freely to a point at
which it can be released, preferably into a gully. The
condensation pipe from the flue to the disposal point should
be of non-corrodible material of not less than 22mm diameter.
Facilities should be made for disconnecting the flue pipe(s)
from the air heater(s) for inspection and servicing purposes.
Bends with removable covers should be fitted for inspection
and cleaning purposes where considered appropriate.
The flue should terminate in a freely exposed position and
must be so situated as to prevent the products of combustion
entering any opening in a building in such concentration as
to be prejudicial to health or a nuisance.
It is recommended that consideration be given to the fitting
of a terminal at the flue outlet, however, where the heater
flue is less than 200mm in diameter an approved terminal
must be fitted.
3.5
Air Supply
In buildings having a design air change rate of less than
0.5/h, and where NCA-G heaters are to be installed in heated
spaces having a volume less than 4.7 m3 /kW of total rated
heat input grilles shall be provide at low level as follows:-
Standard
Larger Horsepower Motor
NOM.
PLATE
START
RUN
FUSE
NOM.
PLATE
START
RUN
FUSE
MOTOR
AMPS
AMPS
AMPS
RATING
MOTOR
AMPS
AMPS
AMPS
RATING
MODEL
ph
R.P.M.
(A)
(A)
(A)
(A)
R.P.M.
(A)
(A)
(A)
(A)
NCA-G 100
1000
2.6
5.0
2.6
3
NCA-G 150
1
500
5.0
8.5
6.1
7
N/A
NCA-G 200
1000
4.1
10.0
4.5
5
NCA-G 300
7.0
18.0
8.1
10
Table 4 Electrical Loadings
3
