1. UL Classification and Current Changes
NAFA 2010 Technical Seminar
Louisville, KY
April 23, 2010

2. Overview Scope of UL 900 Behind the UL Mark Current UL 900 Standard
Classification Testing
Field Inspection
Follow Up Testing
Current UL 900 Standard
Upcoming Changes
Future Work to be Done

3. UL 900 Air Filter Units

4. Scope of UL 900 Air Filter Units
The First Edition of UL 900 was issued in September of 1965
The Current Edition is the Seventh Edition which was issued on September 2, 2004
ANSI/UL consists of the Seventh Edition plus revisions through November 6, 2009
The current revision does not go into effect until May 31, 2012 as noted in the specification

5. Scope of UL 900 Air Filter Units, cont.
From the current effective standard
“cover tests to determine combustibility and the amount of smoke generated for air filter units of both washable and throwaway types used for removal of dust and other airborne particles”
“since the combustibility and smoke generation of an air filter unit, after a period of service, depends upon the nature and quantity of the material collected by the filter, the test requirements of this standard, for classification purposes, apply only to air filter units in a clean condition.”

6. Caution When Reading the Standard or UL Standard Reading 101
UL does not update the latest revision level date on all pages of the standard
Some dates will be for previous issues
Latest revision changes are indicated by vertical lines in the left or right margin
The last two pages of the revision is a summary of the Superseded Requirements
A reference for what was changed
Page numbers are indicated by “sr#”

7. What is Behind the UL Mark?

8. AS TO FLAMMABILITY ONLY
The Current UL Mark
Current UL Classified Mark
Composition and Element
Class 1 or Class 2 Classification
Control Number
Complete Marking includes:
Company Name or File Number
Product Designation
Plant Identification Code
AIR FILTER UNIT
AS TO FLAMMABILITY ONLY
CLASS 1 / CLASS 2
XXXX (Control No.)

9. What goes into UL Classification?
The Life Cycle of a UL Classified Product
Classification Testing
Class 2 Testing
Class 1 Testing
Construction Changes
Field Inspection
Follow Up Testing

10. Flame Exposure Test Apparatus
Air Duct with a blower at one end
Allows for the installation of an air filter unit
Allows for exposure of the air filter unit to an igniting flame under controlled conditions of air velocity
Provides means for observation of the sample filter, and the observation of flame, sparks, and smoke

11. Test Duct Details
Accommodates filters nominal 20x20 and nominal 24x24 with an adapter section
Adapter plates for filters smaller than nominal 20x20
Length of discharge end of the duct is 8 feet measured from downstream face of the filter to end of the duct
Access doors and observation windows on the sides of the duct
Two gas nozzles, 11” apart and 2” off duct floor
Photoelectric cell mounted 12” from end of duct and constant light source to measure smoke generation

12. UL Northbrook Test Duct

13. Classification Testing to UL 900
Class 2 Classification
Shall not produce flame which is sustained beyond the end of the test duct
Shall not produce extensive (25 or more) sparks which are sustained beyond the end of the test duct
Shall not cause the development of an area of more than 58 cm2 (9 square inches) as measured below the smoke-density time curve
Spot flame test not required

14. Classification Testing to UL 900, cont.
Class 1 Classification
Shall not produce flame
Shall not produce sparks
Shall not cause the development of an area of more than 16.1 cm2 (2.5 square inches) as measured below the smoke-density time curve
Spot flame test required

15. New Product Testing To Classify a New Class 2 Product
5 Passing Flame Exposure Tests per Class 2 requirements
To Classify a New Class 1 Product
5 Passing Flame Exposure Tests per Class 1 requirements
1 Spot Flame Test testing in 5 separate filter locations

16. Testing for Construction Changes
Major Changes
Class 1 and Class 2
Same as for New Product
Minor Changes
Class 2
3 Passing Flame Exposure Tests per Class 2 requirements
Class 1
3 Passing Flame Exposure Tests per Class 1 requirements
1 Spot Flame Test testing in 5 separate locations

17. Spot Flame Test 5 locations are tested: frame, media, adhesive
Tested in locations where the flame exposure does not reach
A tip of the blue cone of a gas flame of a Bunsen burner is directed against the upstream face of the sample
Flame adjusted such that it has a 2.5” blue cone, tip temperature 954±27°C(1750±50°F)
Flame is applied for 1 minute then removed.
Filter shall not continue to flame after removal of the test flame to pass

18. Spot Flame Tests

19. Detail of a Spot Flame Test

20. Flame Exposure Test
Air flow is adjusted so that average approach velocity in the duct and the filter face is 220 feet per minute
612 CFM for nominal 20x20, 880 CFM for nominal 24x24
Flow adjusted so discharge velocity is 1 m/s for a nominal 20x20 and 1.4 m/s for a nominal 24x24
Test firing period is 3 minutes
Observations include: condition of both filter faces; density, duration, and character of products of combustion downstream; extent of travel of any flame or sparks beyond the end of the duct
The smoke-density apparatus measures microamperes and the measurement is plotted over time.
Sparks are counted visually at the end of the test duct or by covering the end of the test duct with cheesecloth

21. Flame Exposure Test on Pleated Filter

22. Failed Developmental Flame Exposure Test

23. Field Inspection Quarterly Inspections at each Manufacturing Location
Inspector compares current production to UL File
Inspection annually of all products manufactured
Inspection Includes:
Process
Materials Used
Material Designation
Supplier/Vendor/Manufacturer
Amount of material Used
How materials are measured and check that measurement equipment used is calibrated as required per UL Calibration Requirements

24. Field Inspection, continued
Product Marking
UL mark
Composition and Element
Product Designation
Company Name or File Number
Multiple Listed Product Checks
Split-Inspection Product Checks
Selection of Follow Up Testing Samples

25. Variation Notices
Any deviation from the UL file can lead to a Variation Notice
Variation Notices and Impact are given and the discretion of the inspector for any non-conformances.
Outcomes can include:
Temporary Acceptance of Item(s) affected
Product Hold on Items that are UL marked
Requiring removal of UL marking from manufactured products
Rework of affected items
Re-inspection

26. Variation Notices, continued
Manufacturer must identify root cause of Variation Notice and address the issue listed
UL requires a response to the Variation Notice within a specified amount of time
Correct Issue with production or on product
Test alternate materials/construction
Request a file change
Variation Notice Fine
Additional required inspections also incur the standard inspection fee

27. Follow Up Testing Samples supplied for Follow Up Testing annually
Two samples are required of every type of classified product that each manufacturing location produces
Samples are selected during Field Inspection from current manufacturing or current stock
Each sample is tested for Flame Exposure
Failing one test results in a Variation Notice
The submission of a second set of samples is required
A second failure leads to de-classification of the product

28. Summary of What is Behind UL Marking
Filter Testing
Flame Exposure Testing
Spot Flame Testing
New and Modified Products
Field Inspections
Follow Up Testing
Questions?

29. The Current UL 900 Standard

30. The Current UL 900 Standard
In November of 2009, UL issued a revision to the ANSI/UL 900
Changes go into effect on May 31, 2012
The changes were made after almost a year of work by the Standards Technical Panel (STP) 900 which includes members of the Air Filtration Industry in various Interest Categories:
Producer, Testing and Standards Organizations, Supply Chain, AHJ (Authorities Having Jurisdiction, regional or local authorities), Government, Consumer, General Interest, Commercial/Industrial Users, International Delegates

31. History of the Latest Revision
Proposed by the Industry Group for Air Filter Units
It was noted that Class 1 designation implies a level of protection that is not supported by any test data
Any difference between Class 1 and Class 2 filters are only distinguishable while the filters are tested in the clean state
Once filters are put into service, Class 1 and Class 2 filters behave similarly
Back to the Scope of UL 900, these requirements
“apply only to air filter units in a clean condition.”

32. The Current UL 900 Standard
What is the Impact of the Current UL 900 Standard?
Depends who you ask
UL Standards Committee Members
Manufacturers
UL Engineers
UL Field Inspectors
Underwriters Laboratories of Canada (ULC)
Air Filter Distributors

33. UL 900 Changes Removal of Class 1 and Class 2 references
Products will now just be “UL Classified.”
Classified Products will be tested to current Class 2 standards only.
Spot flame testing will no longer be required
Until the effective date of May 31, 2012, air filters may still be marked Class 1 or Class 2

34. Class 1 and Class 2 Flame Exposure
Class 2 (New Classified)
Class 1 (Discontinued)
No flame beyond the end of the test duct
Less than 25 sparks sustained beyond the end of the test duct
Less than 9 square inches of smoke measured below the smoke-density time curve
No flame produced
No Sparks
Less than 2.5 square inches of smoke measured below the smoke-density time curve

35. AS TO FLAMMABILITY ONLY
New Proposed Marking
Currently PROPOSED Only
UL is still in approval stage
Composition and Element
No Classification wording
Control Number
Complete Marking includes:
Company Name or File Number
Product Designation
Plant Identification Code
AIR FILTER UNIT
AS TO FLAMMABILITY ONLY
XXXX (Control No.)

36. Standard Effective Date May 31, 2012
40 months from the issue of the revision in November 2009, was given to allow Manufacturers time to bring their air filter markings into compliance with the new requirements
All instances must be updated
Labels, die cuts, printing
Additionally: literature, specifications, Customers
Bolder UL Mark – Changed December 15, 1997
Compliance extension to December 31, 2010

37. Manufacturers: Between a Rock and a Hard Place
Manufacturers must be in compliance with the Standard by May 31, 2012
However, Field Inspections are made to the current UL File Classification Marking Page (Class 1/Class 2)
Testing is currently being done is to the current standard (Classified only)
The official marking has not been finalized.
On April 7, UL announced the Industry File Review
Dual Classified Products are a big question mark

38. What’s up with our Friends to the North?

39. Underwriters Laboratories of Canada (ULC)
ULC and UL have a poorly understood relationship
Canadian Standard ULC-S Standard Method of Fire Tests for Air Filter Units
There are subtle differences between ULC-S and UL 900
Canadian Requirements Comparison Guide CRG 900, issued September 2, 2004 compares UL 900 Seventh Edition and ULC-S111 (1995), written by UL
Filters tested at nominal (maximum) rated capacity air flow
Surgical gauze placed at the end of the duct for spark count
Surgical gauze cannot ignite from sparks or flames
Slight differences in duct configuration

40. Current UL/C-UL Marking
UL Files Only
C on the left, US on the right
Canadian only does not have “US” on the right
Class 1 or Class 2 Classification
Control Number
Complete Marking includes:
Company Name or File Number
Product Designation
Plant Identification Code
AIR FILTER UNIT
AS TO FLAMMABILITY ONLY
CLASS 1/CLASS 2
XXXX (Control No.)

41. How does the change to UL 900 affect Dual Classified Filters?
The ULC-S standard has not changed
Filters still Classified to Class 1 and Class 2
The Fire Test Committee controls the Canadian Standard
November 2009 meeting conclusion was that they will not change the Canadian Standard just because UL 900 has changed
Require safety or technical reasons for the change
Will be discussed again in the Spring/Summer meeting
Hopefully, more support from UL
Further uncertainty in marking products

42. UL Proposed UL/C-UL Marking
UL Files Only
Dual UL/C-UL Symbol
No Marking Classification in top portion
Control Number
Class 1 or Class 2 notation for ULC-S111
Complete Marking includes:
Company Name or File Number
Product Designation
Plant Identification Code
AIR FILTER UNIT
AS TO FLAMMABILITY ONLY
XXXX (Control No.)
Class 1/Class 2 in accordance with ULC-S111

43. UL 900 Mentioned in other Standards
NFPA 90A (2009), Standard for the Installation of Air-Conditioning and Ventilating Systems, and the International Mechanical Code (2006) both reference UL 900 but UL has determined that this change will not adversely affect either of these codes
There are a few instances in NFPA 37, Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines, where UL 900 Class 1 filters are specified
Other National, State, Local Building Codes, Customer Specifications
Canadian Building Codes call for Class B (Class 2)

44. Future Work for UL and the Air Filtration Industry
Finalize Marking for US only Classification
Work further with ULC to finalize Dual Marking
Work further with ULC to change ULC-S Standard
Further characterize how the change in UL 900 will affect other standards
Need to develop a unified statement to other regulating bodies
Review Specifications and Standards
Potential Revision regarding clarification of Test Air Flow
UL 900 Clause 7.27: add “airflow” so the test “approach velocity airflow in the duct at the face of the filter is 220 fpm…”

45. Summary on Changes to UL 900
UL 900 latest revision removes Class 1 and Class 2 references
Revision is effective May 31, 2012
Until this date filters may continue to be marked Class 1 and Class 2
Canadian requirements have not changed so filters still need to be marked Class 1 and Class 2 for Canadian Classification
Distributors can sell filters no matter how they are marked, however be prepared to explain what is happening to Customers

46. UPDATE
April 7, 2010, UL sent out a letter to all filter manufacturers with UL 900 Classification
The letter announced the Industry File Review for UL 900 and requires all manufacturers to contact UL by November 30, 2011 to update their files to the latest UL 900 revision (removing Class 1 and Class 2).
UL suggests to manufacturers that this be done sooner than later
Also, manufacturers should request that their Engineer put a descriptive statement in the report to allow for mixed markings during Field Inspections

47. So we end with a bang! Another Failed UL Test

48. Conclusions Always stand BEHIND your UL Engineer when witnessing tests
Boring UL burns – GOOD
Exciting UL burns – BAD
Level of Outcomes of UL Testing
Pass
Fail
Room Clearing Event
Getting the Hose Out
Kevin Getting out his Facemask
Damaging or otherwise affecting equipment in the Test Room

49. Questions? Thank you! Shelby Calvert scalvert@filtrationgroup.com