UL 641:8ED 2010-12

FOREWORD
INTRODUCTION
1. Scope
2. Units of Measurement
3. Components
4. Glossary
CONSTRUCTION
5. Materials
6. Assembly
7. Caps
8. Firestop-Spacers
9. Fittings
10. Joints
11. Radiation Shields
12. Roof Assemblies
13. Roof Jacks
14. Sizes
15. Support Assembly
PERFORMANCE
16. General
17. Test Installation
18. Temperature Measurement
19. Temperature Test - 570 deg F (299 deg C) Flue Gases
20. Temperature Test - 1700 deg F (927 deg C) Flue Gases
21. Draft Loss Test
22. Support Test
23. Strength Test
24. Wind Load Test
25. Rain Test
26. Crushing Test of Nonmetallic Flue-Gas Conduit
27. Resistance to Action of Acids Test of Nonmetallic
     Flue-Gas Conduit
28. Freezing and Thawing Test of Water-Absorptive
     Nonmetallic Materials
29. Cemented Joint Test of Flue-Gas Conduit
30. Sulfuric Acid Extraction Test for Porcelain-Coated
     Steel Used for Flue-Gas Conduit
MARKING AND INSTRUCTION
31. Marking
32. Instructions

This revision of ANSI/UL 641 is being issued to reaffirm approval as an American National Standard.

These requirements cover factory-built vent piping and fittings constructed to provide venting systems for use with gas and liquid fuel-burning appliances that exhaust low-temperature flue gases and that are approved for use with Type L venting systems.