Making Ventilation system safe. Fans are made to many different arrangements and cover a variety of sizes and impeller types. Properly installed, run and maintained, they assist in the creation of better living conditions, cool other equipment, provide essential air for combustion, convey materials, and efficiently carry out many other functions. All fans have moving parts which may require guarding and access doors to duct systems will also be needed.

Making Ventilation home system safe

Noise hazards

Excessive noise can be a health hazard. The sound pressure level at any given location is dependent on the effect of all noise generating equipment and the acoustic environment within the vicinity of the reference point, the fan being only one of the contributing sources. It is, therefore, difficult to predict the sound level without a complete survey of all equipment, orientation of each sound source, acoustical characteristics of the structure, and distances involved to each noise source. Acoustical engineering services should be employed to determine compliance with noise regulations and to make recommendations on any necessary attenuation devices.

Every fan must be provided with a disconnect switch which will allow it to be isolated completely from the electrical supply Most roof-mounted fans and many others are started by remote switches or push-buttons, by interlocks with other equipment, or by automatic controls. In these cases a disconnect switch must be provided close to the fan so that maintenance personnel can “positively” cut off the power when working on the fan.

In some installations other equipment, such as gas burners, may be interlocked with the fans so that disconnecting the fan will automatically shut off the burner or other device. Maintenance on systems of this type should be performed only under the supervision of competent technical staff.

Many fan units are supplied with large quantities of operating and maintenance manuals and other paperwork such as Certificates of Conformity and the like. It is a particular gripe of the author that they are rarely available to the process operators or site maintenance staff. These people need such information on a daily basis, but instead the manuals reside in a project file, gathering dust. Whilst they may be of interest when the plant is duplicated, this is not their purpose.

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Even worse is the situation where the contractor takes out what he thinks is the essential information to give the operatorsW The transition from installation to operation is commissioning and start-up. Commissioning can often be performed by site staff but if they are unfamiliar with any features of the fan then they should seek information from the manufacturer. It is often then possible to combine commissioning with staff training.

When erection is complete, shafts and impellers should be checked for freedom of rotation. As erection proceeds care should be taken to ascertain that no tools, pieces of packing etc, are left in the fan or ducts to cause obstruction or damage when the machine is started up. When direct motor-driven, the direction of rotation of the motor should be checked with the fan, preferably before connecting up to impeller, coupling, or vee belt drive. This is important where special thrust bearings may be employed.

The correct impeller rotation is shown by an arrow on the fan casing. When the machine is driven through a coupling it is particularly important that correct alignment of the two shafts be achieved by checking the coupling by recognised methods for the particular type; levelling up for this purpose is obtained by interposing steel packing between the underside of the bedplate and the top of the foundations.