Maintenance
Air supply systems require routine maintenance to ensure they continue to operate within the original design specifications:

• Inspect the air handler including belts and bearings and service as necessary.
• Inspect heating/cooling coils and ensure the condensate drains are functioning.
• Check the filters and clean or replace as necessary.
  

System Testing
Air supply systems may be tested for a number of reasons, including the following:

• Periodic inspection to ensure the system is performing correctly – for purposes of ensuring general
• occupational safety and health.
• Periodic inspection to ensure the system is dealing with a particular contaminant adequately – for
• purposes of ensuring occupational safety and health
• A new system has been installed and an independent assessment of its performance is required.
• The building has been altered and is it not certain whether the air system is adequate.
• It is suspected that an air system problem is causing discomfort or sickness to building occupants.
• Periodic testing will tend to be the minimum required to verify correct system operation.
• Other testing usually needs to be specially designed to isolate and identify suspected problem areas.
• This testing is usually one time only.

In all cases, a test protocol should be agreed between the client and the test laboratory including the type of tests required, the test locations, and any requirements regarding the time to perform particular tests.

Testing Options from Total Air Care

1. Confirmation of supply air volume and fresh air percentage.
This requires measurement of supply volume and fresh air volume (preferably) or recirculated air volume. In a well designed system, provision will have been made to test these important system parameters.

The test method may involve simple duct-traverse velocity measurements or measurement of supply volumes through supply grilles with a hood, or it may be more involved depending on the system design.

This test should permit confirmation that the system delivers sufficient fresh air to comply with NZ4303, Ventilation for acceptable indoor air quality.

In the absence of any special conditions, this may be sufficient periodic testing for purposes of occupational health and safety.

2. Measurement of CO2 concentration in areas serviced by the air supply system.
This test can in some cases be used as an alternative to the measurement of air supply volumes. If there is sufficient air supply and good mixing of the supply air, the CO2 levels will be low. High levels indicate inadequate fresh air supply or inadequate mixing.

3. Measurement of air quality (particulate).
This involves testing with a particle counter to give an objective measurement of the quality of the air supplied to the area.

Measurements can be taken at the supplies and/or in the areas supplied by the system.

Results can be compared with past results to assess whether the system has deteriorated for any reason. A significant increase in the particle count would indicate either a deterioration in the air intake air quality or a deterioration in filter efficiency.

4. Measurement of microbial concentration.
A measured volume of air (usually 1 cubic metre) is passed over an agar plate which is subsequently incubated and the number of colonies counted. This is a measure of viable particle concentration. If required, the colonies can be identified.

5. Other tests available.