7 March 2012
Comment of HVAC URS >> FROM – TAMASKAR – PLEASE SEE MY REPLY IN “BOLD”.
1. What is the specification for Class E >> THERE IS NO DEFINED SPECIFICATION ANYWHERE. IT IS
UP TO INTERNAL NEED. GENERALLY CLEAN & FILTRATION THRU’ F9 IS ACCEPTABLE.
2. > 5 µM particle in Class A both in at rest and in operation condition should be 1. These areas are
expected to be completely free from particle of size greater than 5 micron , but it is impossible
to demonstrate the absence of particles with any statistical significance, the limits are set to 1
particle/ m3 .. THIS IS INTERNATIONAL NORM AND IT IS NOT “IMPOSSIBLE” TO PROVE AT REST.
3. > 5 µM particle for Class B at rest also set at 1 / m 3 THIS IS INTERNATIONAL NORM AND IT IS
NOT “IMPOSSIBLE” TO PROVE AT REST
4. Temperature limit should be set at 23-27 ° C. >> I HAVE INCLUDED WAREHOUSE ALSO
5. Humidity range 40-60 RH >> I HAVE INCLUDED WAREHOUSE ALSO
6. Differential pressure 2 Pa – 50 Pa ( 0.2 water inches ) >> I HAVE INCLUDED WAREHOUSE ALSO
7. 4.3.2.6 Should include “ Test Adjusting and Balancing “ ( TAB) protocol and report. >> “TEST
PROTOCOL “ WILL DEFINE REQUIREMENTS”
8. 4.3.4.1 Maximum air leakage under 400 Pa 0.003-400 0.65 dm3/s/m2 =0.003-49 the range is very
wide >> THIS IS ACCEPTABLE NORM EVEN FOR ‘CEPHA” hvac.
9. 4.3.5.1 The statement “ withstand the greatest over respectively under pressure that the fans
are capable of producing “ is difficult to understand . Can you write a simpler sentence. >> YES -
REVISED
What does it means, “ Filter cabinets shall be equipped with Clean “FILTER”at the final
inspection” >>
I suggest that all HEPA filter shall be equipment Magnehelic barometer to indicate pressure
drop across the HEPA filter. >> PLEASE REFER 4.3.7.1
10. 4.3.7.1 Can the Magnhelic or equal fix on the “ filter cabinet” measure the pressure drop of each
individual HEPA filter. >> NO, THIS IS NOT POSSIBLE. ONCE THE PRESSURE DIFF. IS HIGH, EACH
INDIVIDAUL “HEPA” NEEDS TO BE TESTED.
11. 4.3.9.1 a protocol is prepared FOR this inspection. Can not understand its meaning.
12. 4.3.9.2 Can you use simpler term for “ not even maximum over –respectively under-pressure
cause deformation” >> OK, DONE.
13. 4.3.11.1 “Perforation through the insulation for e.g. sensor etc shall be done so that risk for
personal injuries do not arise because of sharp plate edges , thread end etc. >> GENERALLY
DURING PERFORATION IF CARE IS NOT TAKEN, SHARP EDGES APPEAR DUE TO LOW THICKNESS.
Question : why perforation can reduce the risk of personal injury of sharp edges.
How to ensure that the perforation will not cause the leakage of the duct. >> THERE
ARE METHODS TO SEAL ALL PERFORATIONS.
14. 4.3.13.10 What is the specification of Ventilation rate test . RATE OF AIR CHANGE , EXHAUST
15. 4.3.13.8 What is the specification of air flow rate. >> REFER THE ROOM DETAILS.
16. 4.3.14.1 The supplier shall deliver basic data for performance that are performed by supplier .
What are these basic data for performance ? >> THESE ARE AGINST SPECIFICATIONS “
17. detail planning of installation in narrow space “
What is the term narrow space means? How about those not narrow space. ? >> SOMETIMES
ENOUGH SPACE IS NOT AVAILABLE. SUCH PLACES HAVE TO BE CAREFULLY PLANNED FOR
INSTALLATION.
18. 4.4.1.3 Each system level works “astronomically” what is astronomically ? >> corrected –
“AUTONOMICALLY”
