Changing Room Problems:

•	Body Odours
•	Condensation

Shower Problems:

•	Steam
•	Condensation

Solutions:

CHANGING ROOMS: Air change rate per hour 6 minimum

The problems present in changing rooms are normally body odours and stale air. Units should be mounted at the opposite end to the entrance door and at high level. As the doors are usually shut, provision should be made for draught-free air replacement. This can be achieved by fitting nonvision grilles in or near the doorways to the lobby, which allow reasonable air transfer but prevent voyeurism.

To meet Building Regulations Document F1, shower areas require 15 litres/second/shower or bath. An area with 6 shower head will therefore need 90 l/s or 324 m³/h. Mains voltage units should be out of reach of persons using a fixed bath or shower. Window mounting fans can be fixed within the depth of the wall and be protected by a suitable grille or louvre.

SHOWER AREA: Air change rate per hour 15-20

Where changing rooms are linked with showers, condensation from the shower can be a problem in the changing area. This can be relieved when the shower area is properly ventilated. The amount of steam given off from a hot shower is considerable and would require a high rate of extraction to remove it quickly. On the other hand, a large amount of air moving through the shower room over naked bodies could cause discomfort and a compromise is necessary.

Calculate for the above air change rates, using speed control to reduce for cooler weather. Extract at high level and if special provision for air replacement is necessary, use high level grilles or windows to reduce the possibility of causing draughts at body level. Overrun timers may be used to ventilate the shower for a period of up to 35 minutes after use.

Heat recovery units will reduce cold draughts and quickly lower internal humidity levels. Toilet suites require 6 l/s per W.C. This should be regarded as a minimum in unsupervised areas, and be doubled for disabled W.C.'s

Size and Number of Ventilation Units

Calculate the volume of the room (height x width x length) and multiply by ACH. This equals the volume required per hour. Choose the size and number of units from the output table to ensure that this minimum volume is achieved.

Axial fans	Output Range
150 mm ø	225 - 285 m³/h
190 mm ø	325 - 425 m³/h
230 mm ø	510 - 710 m³/h
300 mm ø	1190 - 1560 m³/h