| Standard Operating Procedure | SOP No. |
| --- | --- |
| HEPA Filter Leak Test(Oil-Based Challenge) | 8.059 |

DCR No.: 03029  
Revision No.: 0

**Effective**: 10-1-03  
Supersedes: 10-1-03  
Revision Date: 10-1-03  
Page No.: **1 of 4**

## 1

## Purpose

1.1 To establish a standard procedure to insure and confirm the integrity of  
high efficiency particulate air (HEPA) and/or ultra-low penetration air  
(ULPA) filter system installation by verifying the absence of bypass  
leakage in the physical installation and that the filters themselves are free  
of defects and pinhole leaks.

## 2

## Scope

2.1 This procedure applies to leak testing of HEPA and ULPA filters utilizing  
an oil-based challenge.

## 3

## Reference

3.1 National Environmental Balancing Bureau (NEBB) Procedural Standards  
for Certified Testing of Cleanrooms, 1996.

3.2 Institute of Environmental Sciences and Technology (IEST) IEST-RP-  
CC006.2, Testing Cleanrooms.

## 4

## Definition

4.1 HEPA: High Efficiency Particulate Air  
4.2 ULPA: Ultra-Low Penetration Air  
4.3 CFM: Cubic Feet per Minute  
4.4 PSIG: Pounds per Square Inch Gauge

## 5

## Responsibility

5.1 Test and Balance (TAB) technicians shall record all test readings on Form  
FN 8.059.1 (Filter Leak Scan).

5.2 All test reports shall be saved in files, located in the TAB department of  
Therma.

5.3 All test equipment utilized shall be in calibration in accordance with  
National Environmental Balancing Bureau (NEBB) Standards and  
traceable to the National Institute of Standards and Technology (NIST).

## 6

## Materials Requirement

6.1 Dioctylphthalate (DOP) or  
6.2 Poly-alpha olefin (Emery 3004)  
6.3 Ringstand and Clamp

## 7

## Test Equipment

7.1 Source of air-generated aerosol using equipment indicated in NEBB  
Procedural Standards for Certified Testing of Cleanrooms, 1996, Section  
14.6 (Aerosol Generation).

7.2 Aerosol Photometer and Hand Held Probe that meet the criteria in NEBB  
Procedural Standards for Certified Testing of Cleanrooms, 1996, Chapter 6,  
Section 6.2, Subsection 6.2.1, Paragraph 6.2.1.2.

## 8

## Procedures

8.1 Produce a sketch or drawing indicating the relative location of each filter  
that is to be tested.

8.2 Record the clients identification number on the Form FN 8.059.1 (Filter  
Leak Scan).

8.3 Record the filter serial number on the Form FN 8.059.1 (Filter Leak  
Scan).

8.4 Introduce the challenge aerosol into the airstream upstream of the filters  
to be challenged in a manner, which will produce a uniform challenge  
concentration at each of the HEPA filters being exposed at the same  
time.  Follow the procedure found in NEBB Procedural Standards for  
Certified Testing of Cleanrooms, 1996, Chapter 6, Section 6.2,  
Subsection 6.2.2, Paragraph 6.2.2.1.

8.5 Measure the concentration of aerosol in micrograms per liter (µg/l)  
upstream of the filters to be challenged.  Follow the procedure found in  
NEBB Procedural Standards for Certified Testing of Cleanrooms, 1996,  
Chapter 6, Section 6.2, Subsection 6.2.2, Paragraph 6.2.2.2.

8.6 If the upstream challenge cannot be measured and a Laskin Nozzle  
generator is used, the upstream concentration can be calculated.

Concentration of the challenge, when 20 PSIG is available at the Laskin  
Nozzle Generator using DOP, can be calculated by using the following  
formula:

Concentration in µg/l = 13,500(#Laskin Nozzles ÷ CFM)

8.7 Record upstream filter challenge concentration on the Form FN 8.059.1  
(Filter Leak Scan).

8.8 Perform filter leak scanning using the procedures listed in NEBB  
Procedural Standards for Certified Testing of Cleanrooms, 1996, Chapter 6,  
Section 6.2, Subsection 6.2.2, Paragraph 6.2.2.3 and 6.2.2.4.

8.9 Analyze the results using the acceptance standard found in NEBB  
Procedural Standards for Certified Testing of Cleanrooms, 1996, Chapter 6,  
Section 6.2, Subsection 6.2.4, Paragraph 6.2.4.1 for filters that can be  
directly scanned, or a reading greater than 0.005% of the upstream  
challenge aerosol concentration for filters that are scanned indirectly.

8.10 Record filter leak test results, Pass or Fail, on the Form FN 8.059.1 (Filter  
Leak Scan).

8.11 If authorized by the customer, filter repair following the guidelines in  
NEBB Procedural Standards for Certified Testing of Cleanrooms, 1996, Chapter 6,  
Section 6.2, Subsection 6.2.4, Paragraph 6.2.4.2 and/or  
Subsection 6.2.5, “Repairs”.

8.12 After repairs are completed, retest filters utilizing steps 8.4-8.10.

## 9

## Review and Approval

9.1 TAB technicians shall return the Filter Leak Scan form, FN 8.059.1 to the  
TAB Department for review and approval.

## Document Approval

Test & Balance Supervisor

Engineering Manager

Date

Quality Assurance Manager

10/1/03

Date