SOP For Duct Leak Testing

BOTTOMGRASS ENGINEERING & HVAC SERVICES

HVAC Consulting , Installation & Validation Issue Date April 2013

Effective Date April 2013

Standard Operating Procedure Review Date Nil Document Title Procedure Duct Leakage Test Rev R0

Sop No. BG/ES/HV/008/00 Page 1 of 8 1 OBJECTIVE

To lay down a procedure for the Duct Leakage Test

Duct leak testing is to find out actual quantity of air leaking out through duct system and

checkingthe same with standard leakage rate so as to confirm whether leakages in the

system are within limits.

2 SCOPE:

This SOP is applicable for checking Air leak rate from G. I. Ducting.

3 PROCEDURE:

The leak testing rig consist of a fan with fan motor, flow measuring arrangement, flow adjusting ,arrangement & magnehelic guage / PLC Control panel

A] Testing using Analog Magnehelic Gauge & B] Using PLC Control Panel

EQUIPMENT REQUIRED:

a) Blower with motor and Volume control damper

b) Magnehelic Gauges

0 50 mmwc .. 1 No.

0 100 mmwc .. 1 No.

c) Flexible Duct

3.1 Close all Duct Opening with temporary seals

3.2 Calculate the area of Duct in Ft2

Note: The construction class of the Duct as per requirement in Pharma industry is not more than 3. Hence Leakage class (CL) for rectangular duct is 12. (as per Table 4.1)





Sop No. BG/ES/HV/008/00 Page 2 of 8

3.3 Connect the apparatus as per drawing Fig 3.1.

3.4 Connect Magnehelic gauge (0 50 mmwc) across orifice plate.

3.5 Connect high pressure port of 0 -100 mmwc Magnehelic Gauge in the duct and keep the low pressure port of the gauge open to atmosphere

3.6 Adjust Blower to require Static Pressure

3.7 Calculate the Leakage factor (F) by using the relation

CL = F/P0.65 F = CL x P0.65 CL = Duct leakage class

P = Testing pressure in inches of WC.

3.8 Calculate the allowable leakage by using the following expression

Allowable leakage = (Area of duct in Ft2 x F)/100

3.9 Note down the orifice and tube diameter.

3.10 Note down the Differential pressure reading across Orifice.

3.11 Refer table 1.1 and find out the actual Leakage through duct for the corresponding values of Differential pressure.

3.11.1 B] Using PLC Control Panal

3.11.1.1 Connect the Testing Blower to section of ductwork to be tested

3.11.1.2 Start the fan and adjust the flow so as to develop the static pressure in duct 25mm of wg or as per requirement

3.11.1.3 Check the measured leakage is within the permitted rate.

3.11.1.4 Maintain the test for 10 - 15min and check that the leakage rate has not increased

3.11.1.5 Record the test results/print the test results

3.11.1.6 If the leakages are above the permissible limits carryout rectification of leaks by Tightening the duct joints properly with nut-bolts, change the sealant






Reseal the ducts wherever locations have been identified.

3.11.1.7 Repeat the procedure till you get the leakages within permissible limits.

3.12 ACCEPTANCE CRITERIA:-.

a) For 2 testing Pressure leak rate should be Less than or equal to 18.8 CFM / 100 Sqft Duct.

b) For 3 testing Pressure leak rate should be Less than or equal to 24.5 CFM / 100 Sqft Duct.

c) For 4 testing Pressure leak rate should be Less than or equal to 29.5 CFM / 100 Sqft Duct.

3.13 Prepare check sheet for duct leak test as per attached format.





Sop No. BG/ES/HV/008/00 Page 4 of 8 Table 1.1:-

Delta P mm WG Flow Rate CFM Delta P mm WG Flow Rate CFM

1 14.56 26 72.60 2 20.49 27 73.96 3 25.03 28 75.30 4 28.84 29 76.61 5 32.20 30 77.90 6 35.23 31 79.17 7 38.01 32 80.42 8 40.60 33 81.65 9 43.03 34 82.86

10 45.32 35 84.06 11 47.50 36 85.23 12 49.58 37 86.39 13 51.58 38 87.54 14 53.50 39 88.66 15 55.35 40 89.78 16 57.14 41 90.88 17 58.87 42 91.96 18 60.56 43 93.04 19 62.19 44 94.10 20 63.79 45 95.15 21 65.34 46 96.18 22 66.86 47 97.21 23 68.34 48 98.22 24 69.79 49 99.23 25 71.21 50 100.22






y = 14.56x0.493R = 0.998

0

20

40

60

80

100

120

0 10 20 30 40 50 60

Flow

Rat

e (C

FM)

Delta P (mm WC)






4 ABBREVIATIONS

4.1 SOP Standard Operating Procedure No. Number

5 REFERENCES

5.1 SOP BGES-00-800

6 RESPONSIBILITY

6.1 Validation Department.

7 ANNEXURES

7.1 Format for Duct Leakage Test

SOP For Duct Leak Testing

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