HVAC : Acceptable changes for clash free MEP Coordination

To begin with, whatever design drawings we get from the HVAC designer, lets not forget that there is a lot of effort and time gone for this. He would have already considered many factors and constraints to get the design to this level.

Respecting that, the factors which we can change from a HVAC shop drawing are the following:.

DUCT

1. Aspect ratio

The size aspect (height x width) can be changed (width x height) if the airflow is not affected. If the designer allows, even length-width can be changed in measurements also.

2. Offsets

In the initial shop drawings, there will be very little offsets as the designer will be considering only HVAC pipes and ducts. When other MEP services comes in the picture, then there will be areas where it will be needed for more offsets. Again unless the losses are minimum (consult with the designer), then these offsets can be made.

3. Rerouting

Re-routing is another method to avoid clashes. Since, HVAC ducts sizes are generally big, if there is an isolated path which can be taken inside the building, then go for it. This will give other services enough space.

Even in a corridor, as shown in the previous write up, see the side where the feeding is high and shift the main duct accordingly. This will avoid number of crossing which helps in smooth running for other.

4. FCU position

If the FCU's are to be placed in corridors, they need to be closely coordinated with Drainage lines (Plumbing) as the condensation line has to be connected to them. Try to keep the FCU unit at the soffit level unless its a cassette unit. This is feasible when the FCU can be accessed easily for future maintenance. But in case of bigger void areas (for eg. above RCP height greater than 1.5 mtr), the FCU needs to be lowered for easy access to repair and maintain in future.

CHWP

For chilled water pipes which is also an HVAC service, can also go for changes mentioned in point no. 2 and 3. Offsets and rerouting can be done extensively as these are forced water circulation. But it should be done before the manufacturing order for the offset piece and bends are given.

NB: The changes above mentioned are not mandatory if there are ways to avoid clash by co-ordinating other services. As mentioned before, the installation of HVAC is most cumbersome and hence try to give them minimum trouble.

Next is Plumbing system - the exercises that can be done wrt MEP co-ordination.