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Helpful Notes |
Building Regulations
A copy of the 2006 edition of the Building Regulations for Ventilation Requirements can be found here.
Recommended Air Changes
A step-by-step guide
Choosing the correct fan for the job depends on two main criteria, performance required and application.
Performance required
To calculate the performance required, establish the following information:
1.Room volume
Length x Width x Height
2.Number of air change per hour required
| Situation | ACH |
| Assembly Rooms | 6 - 8 |
| Bakeries | 20 - 30 |
| Banks | 4 - 6 |
| Bathrooms | 3 - 8 |
| Cafes | 10 - 12 |
| Car park, Basement & Ramps | 3,6 & 10 |
| Cellars | 3 - 10 |
| Changing Room | 6 - 10 |
| Cinemas & Theatres | 6 - 10 |
| Conference Rooms | 8 - 12 |
| Dance Halls | 10 - 12 |
| Garages | 6 - 10 |
| Glasshouses | 45 - 60 |
| Gymnasiums | 6 - 8 |
| Hairdressing Salons | 10 - 15 |
| Kitchen - Domestic | 10 - 15 |
| Kitchen - Commercial | 18 - 25 |
| Laboratories | 4 - 6 |
| Laundries | 10 - 15 |
| Lecture Theatres | 6 - 10 |
| Libraries & Museums | 3 - 4 |
| Offices | 4 - 6 |
| Restaurants - no smoking | 8 l/s per person |
| Restaurants - smoking | 16 l/s per person |
| School Rooms | 4 - 6 |
| Shopping Centres | 1 l/s per m3 |
| Shops & Supermarkets | 8 - 10 |
| Shower Rooms | 15 l/s per shower |
| Stores & Warehouses | 3 - 6 |
| Swimming Baths | 10 - 15 l/m2 of water surface |
| Toilets | 6 l/s per WC or 5 ach |
| Utility Rooms | 15 - 20 |
| Waiting Rooms | 6 - 10 |
| Workshops | 6 - 10 |
Performance required = room volume x number of air changes
Check that this exceeds the minimum requirements of the Building Regulations, taking into account ducting arrangements etc
Application
The choice of wall, window or ceiling fixing is available to suit the application. If installation is to be in the ceiling, choose the shortest, smoothest duct route possible. Now choose the type of fan to do the job – axial or centrifugal.
Example
| Room | Domestic Kitchen |
| Volume (size) | 3 x 3 x 2.5 = 22.5 m3 |
| Air Changes per Hour | 10 |
| Performance | 22.5 x 10 = 225m3/hr |
| Fixing | ceiling |
| Fan Type | Centrifugal |
| Fan Required | CF200 series |
Conversion Table
Fluorescent Lamps
Many fluorescent lamps and low energy lamps emit substantial power pulses (spikes) when turned on and off (over 2 kV). Ferrob fans are tested to accept occasional high voltage pulses as part of standards requirements.
However, repeated high voltage pulses can cause premature ageing of electronics and can destroy components. If a specification requires fans fitted with electronic controls (timer, humidistat etc.) to be installed in conjunction with fluorescent lamps, we recommend that a power filter (ANC 811A or ANC831A) be fitted to the fan power supply.
Fans without electronics are unaffected by fluorescent lamps. This applies to all currently available extractor fans known to us.
Specification Notes
All Ferrob products are subject to on-going product development and we therefore reserve the right to alter any specification without notice. Variations may apply to the extract performance figures quoted. Any published noise levels and extract performance figures should be taken as guidance only as individual product and installation may vary.
Ducting Notes
Fan performances will vary depending on the types of grilles and cowls used.
Electrical Installation
If in doubt regarding the installation of any Ferrob product, we strongly recommend you consult a qualified electrical engineer before proceeding.
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