How to measure Air CFM in HVAC Duct using Extech Anemometer

[pakblogger2012]

May I request senior members to guide me regarding the standard method for measurement of CFM in hvac duct using Extech Instrument.
Please do include information and tips related to following questions.

1. Anemometer should be used in open mouth duct .with diffusers or without diffusers ?
2. Which size should we use for CFM ,diffuser size or upstream duct size,or neck size ?
3. If used at with diffuser,at how many positions and angle should we take readings? I have observed much difference in velocity at different locations of diffuser.
4. What should be position of return air damper for a room,should it be kept at fully open or partially closed position ?
5. How much error should we accept in CFM while commissioning an HVAC System? Please elaborate with relevant codes and standards.
6. How to verify the CFM and static of AHUs,?

Waiting for your kind urgent reply

[frank]

Have a read of this informative book......it should help you understand the basics.

[pakblogger2012]

very informative book sir,
I expect some practical and to the point tips sir,
thanks sir

[frank]

very informative book sir,
I expect some practical and to the point tips sir,
thanks sir

I think you would find it more helpful if you read the book first, try to understand the basics and then came back with specific questions about what you don't understand so that the members can assist you that way.

[pakblogger2012]

Already studying that book sir,
Actually I am short of time , tomorrow I have to do that sort of work ,that,s why I requested sir.
Thanks

[Brian_UK]

Do not start running until you have learnt to walk.