Roberts Gorden POP-ECA/PGP-ECA 015 to 0100 AIR SUPPLY 7.1 Air Supply, Isolated Equipment Rooms

SECTION 7: AIR SUPPLY

SECTION 7: AIR SUPPLY 7.1 Air Supply

It is important to ensure adequate air supply at all times for both combustion and heating requirements in accordance with BS 6230 for UK installations and the latest revisions of applicable standards and local and national codes.

7.2 Isolated Equipment Rooms

Ventilation must prevent the temperature of isolated equipment room from exceeding 32°C as well as prevent any negative air pressure within the room. Any isolated equipment room containing air heaters will require permanent air vents direct to outside air in compliance with local codes.

Where natural ventilation is used, suitable permanent openings at low and high levels, communicating directly with the outside air, must be provided.

Where mechanical ventilation is used, extract rate must be 5% - 10% less than the inlet rate. The mechanical ventilation must be interlocked with the burner on the heater.

7.2.1Heaters Installed Within the Heated Space Where the volume of the heated space is greater than 4.7 m3 per kilowatt of total rated heat input and the air change rate is at least 0.5/h, additional high and low level ventilation will not be required.

For a building having an air change rate less than 0.5/h, ventilation will be necessary in accordance with local and national codes.

7.3 Building Ventilation

Where ventilation is required, air must be taken from an outside point where it is not likely to be contaminated or obstructed.

7.4 Distribution Ducting

Duct should be full size for at least twice the minor dimension before change of direction or reduction of area.

7.5 Return Air Ducting

In installations employing recirculation or fresh air ducting, this ducting shall comply with the following:

1.There shall be an unobstructed air path con- nected directly to the heater.

2.The return air or fresh air shall be connected by ducting directly to the air inlet on the heater.

3.Where automatic or manual dampers are pro- vided for operational adjustment in these ducts, they shall be proved in the correct position dur- ing the operation of the burner.

The main fan requires a minimum free air return path of 1 m2 per 197 kW of heater output or 0.33 m2, whichever is greater.

NOTE: When heaters are installed in the horizontal mode and connected to distribution ducting and/or inlet ducting, then the natural convected air flow through the heater, before the main fan turns on may be disrupted.

To ensure correct operation of the fan under these circumstances, in all COMBAT® cabinet heaters designed for horizontal mounting, the main fan will operate in conjunction with the burner sequence by the use of a time delay or direct acting relay.

It is strongly recommended that when any heater is connected to installation ducting, a similar approach to the fan control is used. Any such control must be in parallel with the fan thermostat so that the fan "run on" feature is still able to operate (See Page 22, Section 9.5).

15