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INSTALLED FILTER LEAKAGE TEST

PROCEDURE

INSTALLED FILTER LEAKAGE

TEST PROCEDURE

7/25/2019 Installed Filter Test Procedure

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INSTALLED FILTER LEAKAGE TEST

PROCEDURE

I. Purpose:

- To check leakage between filter box and filter frame.

- To check the integrity of filter (fault of filter media)

The installed filter is passed if no leakage detected in two tests above.

Figure 1

- During the measurement in case of found particle which size is over 0.3 micro meters, stop

measurement and confirm the counting of particle.

- In case of no increase counting, it is understood as stuck particle and continues sampling.

II. Measuring device:

No. Device Manufacturer Model Origin Serialnumber

1 AnemometerPROVA

InstrumentAVM-03 Taiwan 9300447

2Particle

counterKANOMAX 3887A Japan 23713

III. Preparation works before testing:

Check the air duct, ensure the ducts are correctly installed. The room is cleaned to reach clean

room cleanliness and there is no particle generated inside of room.

IV. Testing procedure: (comply with Annex B.6 ISO 14644-3 2005)

1. Measure face velocity on filter

2. Measure concentration of 0.3 m particle above filter to define Cc[particles/cm3]

3. Based on filters efficiency, define maximum allowable integral MPPS (Most PenetratingParticle Size) penetration of the filter.

HEPA filter

HEPA filter

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INSTALLED FILTER LEAKAGE TEST

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For example, if the filters efficiency is 99.95% against particles of size 0.15 0.3 m then

Ps= 0.05%

4. From the table below, we have factor K = 10

Ps 5 x 10-4 5 x 10-5 5 x 10-6 5 x 10-7 5 x 10-8

K factor 10 10 30 100 300

5. Standard leak penetration of the filter PL= K.PS

6. Scan rate of probe is calculated from:

Sr [Cc(PL Ps) qvs+Ccx Psx qva] (Dp/Np)Where

Cc: particle concentration above HEPA filter, [particles/cm3];

Ps: maximum allowable integral MPPS (Most Penetrating Particle Size) penetration of the

filter;

PL: standard leak penetration of the filter;

qvs: standard flow rate, qvs= 1 ft3/s = 472 cm3/s (28.3 l/min);

qva: actual flow rate of particle counter (cm3/s);

Dp: probe dimension parallel to the scan direction (cm);

Np: expected number of particle counts [particles]; Npis paired with Cain Poisson table

Ca: observed acceptable count [particles]; Cais chosen from Poisson distribution table

NOTE: Srshould not exceed 8 [cm/s], if the calculated Sris over 8 [cm/s] then Np, Cais re-

calculated with Sr= 8 [cm/s].

Upper limit of the 95% confidence interval of a Poisson distribution

Observed

Ca

Upper limit

Np

Observed

Ca

Upper limit

Np When Npis

larger than 19.7

Ca= Np- 2Np

0 3.7 6 13.1

1 5.6 7 14.4

2 7.2 8 15.8

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3 8.8 9 17.1

4 10.2 10 18.4

5 11.7 11 19.7

Any observed counts greater than Cais sign of potential leak

NOTE: While scanning, probe should be maintained at a distance of 3 cm from filter face.

7. Stationary measuring is proceed if a potential leak is detected. At potential leak, re-

measure particle in sustained residence time T r, Trshould be set at one or a few times the

fixed interval of particle counter. Caof stationary measuring is calculated from equation Ca=

Npa- 2Npa

Npais calculated from equation : Npa= [Cc(PL Ps)qvs+ Ccx Psx qva]Tr

8. The installed filter leakage testing includes two stages:

- Stage one: Proceed scanning along filter gasket to check leakage between filter box

and filter frame

- Stage two: Proceed scanning filter surface to check the integrity of filter

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Date:

S/N

Dimension

AHU No.

Room

Note: Resisdence time, s

No.Scanning

counts

Stationary

counts

Leaked

(Yes/No)No.

Scanning

counts

Stationary

counts

Leaked

(Yes/No)

Scanning

limit,

counts

Stationary

limit,

counts

Filter material scanning Filter frame scanning

FILTER PASSED LEAKAGE TEST (YES/NO)

INSTALLED FILTER LEAKAGE TEST REPORT

TEST RESULTS

Challenging

particles

concentration

(particles/cm3)Location

Filter

Testing criteria

Scanning

rate, cm/s