1、UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL 268A Smoke Detectors for Duct ApplicationUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM ULUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR
2、FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL UL Standard for Safety for Smoke Detectors for Duct Application, UL 268A Fourth Edition, Dated December 11, 2008 Summary of Topics Reaffirmation and Continuance of the Fourth Edition of the Standard for Smoke Detectors for Duct Applicat
3、ion, UL 268A, as an American National Standard. Text that has been changed in any manner or impacted by ULs electronic publishing system is marked with a vertical line in the margin. The revised requirements are substantially in accordance with Proposal(s) on this subject dated August 1, 2014. All r
4、ights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form by any means, electronic, mechanical photocopying, recording, or otherwise without prior permission of UL. UL provides this Standard as is without warranty of any kind, either expr
5、essed or implied, including but not limited to, the implied warranties of merchantability or tness for any purpose. In no event will UL be liable for any special, incidental, consequential, indirect or similar damages, including loss of prots, lost savings, loss of data, or any other damages arising
6、 out of the use of or the inability to use this Standard, even if UL or an authorized UL representative has been advised of the possibility of such damage. In no event shall ULs liability for any damage ever exceed the price paid for this Standard, regardless of the form of the claim. Users of the e
7、lectronic versions of ULs Standards for Safety agree to defend, indemnify, and hold UL harmless from and against any loss, expense, liability, damage, claim, or judgment (including reasonable attorneys fees) resulting from any error or deviation introduced while purchaser is storing an electronic St
8、andard on the purchasers computer system. The requirements in this Standard are now in effect, except for those paragraphs, sections, tables, gures, and/or other elements of the Standard having future effective dates as indicated in the note following the affected item. The prior text for requiremen
9、ts that have been revised and that have a future effective date are located after the Standard, and are preceded by a SUPERSEDED REQUIREMENTS notice. OCTOBER 2, 2014 UL 268A tr1UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL OCTOBER 2, 2014
10、UL 268A tr2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL DECEMBER 11, 2008 (Title Page Reprinted: October 2, 2014) 1 UL 268A Standard for Smoke Detectors for Duct Application Some requirements specied in this standard
11、were previously covered in the Standard for Combustion Products Type Smoke Detectors for Fire Protective Signaling Systems, UL 167, and Photoelectric Type Smoke Detectors for Fire Protective Signaling Systems, UL 168. First Edition May, 1983 Second Edition March, 1993 Third Edition May, 1998 Fourth
12、Edition December 11, 2008 This ANSI/UL Standard for Safety consists of the Fourth Edition including revisions through October 2, 2014. The most recent designation of ANSI/UL 268A as a Reaffirmed American National Standard (ANS) occurred on October 2, 2014. ANSI approval for a standard does not inclu
13、de the Cover Page, Transmittal Pages, Title Page, or effective date information. Comments or proposals for revisions on any part of the Standard may be submitted to UL at any time. Proposals should be submitted via a Proposal Request in ULs On-Line Collaborative Standards Development System (CSDS) a
14、t http:/. ULs Standards for Safety are copyrighted by UL. Neither a printed nor electronic copy of a Standard should be altered in any way. All of ULs Standards and all copyrights, ownerships, and rights regarding those Standards shall remain the sole and exclusive property of UL. COPYRIGHT 2014 UND
15、ERWRITERS LABORATORIES INC. ANSI/UL 268A-2009 (R2014)UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT APPLICATION - UL 268A 2 No Text on This PageUL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER RE
16、PRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL CONTENTS INTRODUCTION 1 Scope .7 2 General 8 2.1 Components .8 2.2 Units of measurement .8 2.3 Undated references .9 3 Glossary .9 4 Installation and Operating Instructions 10 CONSTRUCTION 5 Enclosure .10 5.1 General 10 5.2 Cast metal enclosures
17、.11 5.3 Sheet metal enclosures 11 5.4 Nonmetallic enclosures .12 5.5 Covers .14 5.6 Glass panels 15 6 Remote Accessories .15 6.1 General 15 6.2 Sensitivity indicating means .16 6.3 Radioactive materials 16 7 Air Flow Monitoring 17 7.1 General 17 7.2 Alignment and secureness .17 8 Protection Against
18、Corrosion 17 9 Field-Wiring Connections .18 9.1 General 18 9.2 Field wiring compartment .18 9.3 Field wiring terminals 18 9.4 Field wiring leads 19 9.5 Grounding terminals and leads 19 9.6 Grounded supply terminals and leads 20 9.7 Isolated (nongrounded) detectors 20 10 Internal Wiring 21 10.1 Gener
19、al .21 10.2 Wireways 22 10.3 Splices 22 10.4 Barriers .22 10.5 Strain relief 22 11 Bonding for Grounding 23 COMPONENTS 12 General 24 12.1 Mounting of components 24 12.2 Operating components 25 12.3 Current-carrying parts .25 13 Bushings 25 DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT APPLICATION - UL
20、268A 3UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 14 Electrical Insulating Material 26 15 Lampholders and Lamps 27 16 Photocell Illuminating Lamps .28 16.1 General .28 16.2 Operating conditions LED .28 17 Motors .28 18 Protective Devices
21、 28 19 Printed Wiring Boards .29 20 Switches .29 21 Transformers and Coils 29 22 Dropping Resistors 29 SPACINGS 23 General 30 24 Servicing and Maintenance Protection .31 24.1 General .31 24.2 Sharp edges .32 PERFORMANCE 25 General 32 25.1 Test units and data .32 25.2 Test voltages 32 25.3 Test sampl
22、es and data 33 25.4 Component reliability data .34 25.5 Remote accessories 34 25.6 Detector head tests .35 26 Normal Operation Test 35 27 Electrical Supervision Test .35 27.1 General .35 27.2 Component failure 37 27.3 Photocell illuminating lamps .37 28 Circuit Measurement Test 38 29 Air Leakage Tes
23、t .38 30 Overvoltage and Undervoltage Test .38 30.1 Overvoltage test .38 30.2 Undervoltage test 39 31 Temperature Test .39 32 Vibration Test 42 33 Component Replacement Test .43 34 Jarring Test 43 35 Cover Replacement Test 44 36 Fire Tests 45 36.1 General .45 36.2 Combustibles 46 36.3 Test equipment
24、 47 36.4 Typical duct testing facility .51 36.5 Test methods 52 37 Stability Tests 58 38 Variable Ambient Temperature Test .58 38.1 Operation in high and low ambients 58 38.2 Effect of shipping and storage .59 DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT APPLICATION - UL 268A 4UL COPYRIGHTED MATERIAL
25、NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 39 Humidity Test 59 40 Corrosion Test .59 41 Transient Test 61 41.1 General .61 41.2 Internally induced transients .61 41.3 Extraneous transients .61 41.4 High-voltage transients 62 42 Static Discharge Test .62 43 Ove
26、rload Test 63 43.1 Internally energized circuits 63 43.2 Separately energized circuits 63 44 Endurance Test 64 44.1 Internally energized circuits 64 44.2 Separately energized circuits 64 45 Abnormal Operation Test 64 46 Locked Rotor Test 65 46.1 General .65 46.2 Thermal or overcurrent protection 65
27、46.3 Impedance protection .66 47 Dielectric Voltage-Withstand Test .67 48 Polarity Reversal Test .67 49 Tests of Polymeric Materials .68 49.1 General .68 49.2 Temperature test .68 49.3 Flame test .68 49.4 Conduit connections 69 50 Tests of Elastomeric and Foam Materials 71 50.1 General .71 50.2 Acce
28、lerated aging 71 51 Strain Relief Test .71 52 Radioactive Material Measurement Test .72 53 Sensitivity Tests of Smoke Sensing Chamber(s) 72 MARKING 54 General 73 55 Installation Wiring Diagram .75 56 Technical Bulletin .76 57 Packaging Marking 77 SUPPLEMENT SA - INSTRUCTIONS FOR DETERMINING A RELIAB
29、ILITY PREDICTION OF ELECTRONIC COMPONENTS AND MICROELECTRIC CIRCUITS SA1 Methods of Determining Failure Rate SA1 DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT APPLICATION - UL 268A 5UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL SUPPLEMENT SB
30、- CRITERIA FOR ACCEPTANCE OF MICROELECTRONIC DEVICES SB1 General SB1 SB2 Part I Quality Assurance Screening Program SB1 SB3 Part II Determination of Failure Rate Number Supplemented by Burn-in Test .SB4 SB3.1 General SB4 SB3.2 Determination sequence .SB4 SB3.3 Test calculations and procedures .SB4 S
31、B3.4 Test conditions .SB7 SB3.5 Failure rate number calculation .SB7 APPENDIX A Standards for ComponentsA1 APPENDIX B Analysis of Radioactive Elements DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT APPLICATION - UL 268A 6UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WIT
32、HOUT PERMISSION FROM UL INTRODUCTION 1 Scope 1.1 These requirements cover air duct smoke detectors intended for indoor use within or protruding into a duct, or mounted in a housing with sampling tubes extending into or traversing a duct. Air duct smoke detectors are intended to be installed in ducts
33、 where the maximum air temperature inside the duct does not exceed 100F (38C), nor does the minimum temperature become less than 32F (0C), in accordance with the Standard for Automatic Fire Detectors, NFPA 72, and the Standard for the Installation of Air Conditioning and Ventilating Systems, NFPA 90
34、A. 1.2 An air duct smoke detector unit, as covered by these requirements, is intended to detect smoke for the primary purpose of controlling blowers and dampers of air conditioning and ventilating systems to reduce the risk of panic and damage from distribution of smoke and gaseous products. Each un
35、it consists of an assembly of electrical components, including a sensing means to detect smoke (sensing head or projected beam assembly), sampling tubes or equivalent (based on design), provision for connection to a source of power, and means for generating a signal when smoke is detected. It is not
36、 prohibited that remote control circuits be provided. A detector shall be powered from a commercial power source, separate power supply, or be connected to a control unit as part of a re protection signaling system. Duct detectors are not intended as a substitute for open area protection. 1.3 These
37、requirements cover detectors: a) Intended to control air conditioning and ventilating systems, b) Intended for control of releasing devices, such as re and smoke dampers, or c) Both (a) and (b). 1.4 These requirements do not cover: a) Control units that are covered by the Standard for Control Units
38、and Accessories for Fire Alarm Systems, UL 864, to which the air duct smoke detectors are connected. b) Single and multiple station smoke detectors covered by the Standard for Single and Multiple Station Smoke Alarms, UL 217. c) Smoke detectors intended for open area protection or releasing device s
39、ervice, or both, covered by the Standard for Smoke Detectors for Fire Alarm Signaling Systems, UL 268. d) Smoke detectors integral with combination door closers and holders, covered by the Standard for Door Closers-Holders, With or Without Integral Smoke Detectors, UL 228. e) Commercial-resident det
40、ectors not intended for connection to a system control unit that are covered by the Standard for Smoke Detector Monitors and Accessories for Individual Living Units of Multifamily Residences and Hotel/Motel Rooms, UL 1730. DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT APPLICATION - UL 268A 7UL COPYRIGH
41、TED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 1.5 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of re or of elec
42、tric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conict with sp
43、ecic requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard. 2 General 2.1 Components 2.1.1 Except as indicated in 2
44、.1.2, a component of a product covered by this standard shall comply with the requirements for that component. See Appendix A for a list of standards covering components usually used in the products covered by this standard. 2.1.2 A component is not required to comply with a specic requirement that:
45、 a) Involves a feature or characteristic not required in the application of the component in the product covered by this standard; or b) Is superseded by a requirement in this standard. 2.1.3 A component shall be used in accordance with its rating established for the intended conditions of use. 2.1.
46、4 Specic components are incomplete in construction features or restricted in performance capabilities. Such components are intended for use only under limited conditions, such as certain temperatures not exceeding specied limits, and shall be used only under those specic conditions. 2.2 Units of mea
47、surement 2.2.1 When a value of measurement is followed by a value in other units in parentheses, the rst stated value is the requirement. 2.2.2 Unless otherwise indicated, all voltage and current values specied in this standard are root-mean-square (rms). DECEMBER 11, 2008 SMOKE DETECTORS FOR DUCT A
48、PPLICATION - UL 268A 8UL COPYRIGHTED MATERIAL NOT AUTHORIZED FOR FURTHER REPRODUCTION OR DISTRIBUTION WITHOUT PERMISSION FROM UL 2.3 Undated references 2.3.1 Any undated reference to a code or standard appearing in the requirements of this standard shall be interpreted as referring to the latest edi
49、tion of that code or standard. 3 Glossary 3.1 For the purposes of this standard the following denitions apply. 3.2 COMBINATION SMOKE DETECTOR A smoke detector that employs more than one smoke detecting means in one unit. In a combination smoke detector either each principle predominates, or contributes in response to at least one of the re tests described in Fire Tests, Section 36. 3.3 COMPONENT, LIMITED-LIFE A component that is expected to malfunction and be periodically replaced, and the malfunctio
