ANSI ALI LADDER A14.1-2007 Ladders - Wood Safety Requirements.pdf

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1、ANSI-ASC A14.1-2007American National StandardsAmerican NationalStandard for Ladders Wood Safety Requirements ANSI-ASC A14.1-2007Revision of ANSI A14.1-2000American National Standardfor Ladders-Wood SafetyRequirements SecretariatAmerican Ladder InstituteApproved August 20, 2007American National Stand

2、ards Institute, Inc.For information on possible errata sheets and other ANSI -ASCA14 Standards please refer to the ALI website located at:www.americanladderinstitute.orgAn American National Standard implies a consensusof those substantially concerned with its scope andprovisions. An American Nationa

3、l Standard is intendedas a guide to aid the manufacturer, the consumer, andthe general public. The existence of an AmericanNational Standard does not in any respect precludeanyone, whether they have approved the standard ornot, from manufacturing, marketing, purchasing, orusing products, processes,

4、or procedures not conformingto the standard. American National Standards are subjectto periodic review and users are cautioned to obtain thelatest editions.The American National Standards Institute does notdevelop standards and will in no circumstances givean interpretation of any American National

5、Standard.Moreover, no persons shall have the right or authorityto issue an interpretation of an American NationalStandard in the name of the American NationalStandards Institute.Caution Notice: This American National Standard maybe revised or withdrawn at any time. The procedures ofthe American Nati

6、onal Standards Institute require thataction be taken to reaffirm, revise, or withdraw thisstandard no later than five years from the date of publi-cation. Purchasers of American National Standards mayreceive current information on all standards by callingor writing the American National Standards In

7、stitute.Published byAmerican Ladder Institute401 N. Michigan Avenue, Chicago, IL 60611Copyright 2007 by ANSI-ASC A14All rights reserved.No part of this publication may be reproduced in anyform, in an electronic retrieval system or otherwise,without the prior written permission of the publisher.Print

8、ed in the United States of AmericaAmerican National StandardII(This Foreword is not a part of American NationalStandard A14.1-1994.)This standard is a revision of American NationalStandard Safety Requirements for Portable WoodLadders, ANSI A14.1-2000. It is one of a series ofmany standards prepared

9、under the supervision ofAmerican National Standards Committee on Safety inthe Construction, Care, and Use of Ladders, A14. All of the standards have been developed by subcommitteesreporting to American National Standards CommitteeA14. The subcommittees are: A14.1, Portable WoodLadders; A14.2, Portab

10、le Metal Ladders; A14.3, FixedLadders; A14.4, Job-Made Ladders; A14.5, PortableReinforced Plastic Ladders; and A14.9, Ceiling MountedDisappearing Climbing Systems.All standards, with the exception of A14.7-1991, MobileLadder Stands, derive from the original AmericanNational Standard Safety Code for

11、Construction, Care,and Use of Ladders, A14, which was first approved in1923. Revisions were approved in 1935, 1948, and 1952.The earlier editions contained some treatment of metaland fixed ladders. Requirements for these types of lad-ders were removed from the 1948 revision because rapiddevelopment

12、in the metal ladder field warranted specialconsideration and treatment of metal ladders and fixedladders (usually metal) in separate standards. In 1948,the code was revised and its title and designationchanged to American National Standard Code for WoodLadders, A14.1. In 1952, it was again revised a

13、nd reti-tled American National Standard Safety Code forPortable Wood Ladders. It was further revised in 1959,1968, 1980, and 1982.Responding to a Consumer Product Safety Commissionchallenge in August 1975, the A14 Committee mounted athree-prong attack to upgrade the portable ladder standardswithin t

14、he consensus framework of developing standards.Three Task Forces Anthropometric, Testing, andLabeling were established in October 1975.Without question, the most massive and technicallydifficult task, which included a significant amount ofhuman-factors work, was carried out by the TestingTask Force.

15、 Over 100 known ladder experts weresolicited to join this task force and provide their techni-cal expertise. The work involved 50 meetings, over 400test documents, and the use of numerous test laddersover a period of nearly two years. The cost of the projecthas been conservatively estimated at over

16、$300,000.At the August 11, 1977, joint meeting of the TestingTask Force and the A14 Advisory Committee, 23procedures were presented. These procedures, with an accompanying rationale based upon statistical andhuman-factors data, were distributed to the threeportable-ladder subcommittees for review an

17、d incorporationinto the standards. Recommendations for nomenclatureand for care and use of ladders have been included in theAppendixes, had been previously balloted in order thatthis more technical material from the Testing Task Forcereceive the full attention of the three subcommittees.Test procedu

18、res were developed for three differentapplications; namely, design verification, qualitycontrol, and in-service testing. Design verification testswould generally be conducted on a one-time basis dur-ing the original design development of the product andwould usually be destructive tests. Quality con

19、trol testswould be conducted by the manufacturer on an on-goingbasis; some of the tests would be destructive and somewould be nondestructive. In-service tests would beconducted by the user on a periodic basis and wouldbe nondestructive in nature.The A14 Committee adopted June 4, 1982*, as the effect

20、ive date of ANSI A14.1-1981. This was to allowthe manufacturers the necessary lead time to evaluatetheir products for conformance to the 1981 edition of the three portable-ladder standards, to redesign and testtheir products where applicable, to design and build therequired manufacturing tooling and

21、 machinery, and toconvert their manufacturing operations to produce therevised products.ForwardIIIErick Knox, ChairmanDon Gibson, Vice ChairmanRon Pietrzak, Administrative SecretariatOrganization Represented Name of RepresentativeAmerican Insurance Association . . . . . . . . . . . . . . . . . . . .

22、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . George EarhartThomas Murray (Alt)American Ladder Institute. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Marc McConnellAmerican Society of Safety Engi

23、neers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Earnest HarperMichael Lorenzo (Alt)Associated General Contractors of America . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Charles Bird

24、Canadian Standards Association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Walter DickCosco Home and Office Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25、 . . . . . . Eric KruseTerry Emerson (Alt)Disappearing Attic Stairway Association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dennis WilliamsBrad Hudspeth (Alt)Illinois Association of Building Maintenance Contractors . . . . . . . . . . . . . . .

26、 . . . . . . . . . . . . . . . . . . . . . . . Carl Pedersen James Weil (Alt)International Brotherhood of Electrical Workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . James TomaseskiInternational Brotherhood of Painters and Allied Trades . . . . . . . . .

27、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dan PenskiMike Metz (Alt)International Union of Bricklayers in suchcases, they are often indicated by “fiber breakage” onend grain surfaces.(4) Compression wood. An aberrant, highly variabletype of wood structure with abnormal cells occ

28、urringin many softwood species.(5) Cross grain (slope of grain). A deviation of thefiber direction from a line parallel to the sides of thepiece. Cross grain may be diagonal or spiral, or both.(6) Decay. The disintegration of wood due to the actionof wood-destroying fungi; also known as wood rot.(7)

29、 Knot. A portion of a branch or limb, embeddedin the tree and cut through in the process of lumbermanufacture. It is classified according to size, quality,occurrence, and location in the cross section of apiece. The size of the knot is determined by its averagediameter on the surface of the piece.(8

30、) Low-density wood. Wood that is exceptionallylight in weight and usually deficient in strengthproperties for the species. In softwood species, lowdensity is frequently indicated by exceptionally wide,or sometimes by extremely narrow, rings, and generallya low proportion of latewood. On the other ha

31、nd, low-density hardwood, at least in ring-porous species, ismost commonly indicated by excessively narrow annualrings in which the earlywood portion predominates.(9) Pitch pocket. An opening extending parallel tothe annual growth rings that contains, or that hascontained, either solid or liquid pit

32、ch.(10) Shake. A separation along the grain, occurringmost often between the rings of annual growth.(11) Split. A separation of the wood parallel to thefiber direction due to tearing apart of the wood fibers,normally caused by external forces.(12) Wane. Bark, or lack of wood, on the corner ofa piece

33、.Working length. The length of a non-self-supportingportable ladder measured along the rails from the basesupport point of the ladder to the point of bearing at the top.Working load. The maximum applied load, includingthe weight of the user, materials, and tools that the ladderis to support for the

34、intended use.5. Materials5.1 Requirements for Wood Parts5.1.1 Requirements Applicable to All Wood Parts.5.1.1.1 General Requirements. All wood parts ofthe species specified in Table 1 shall be seasonedat the time of manufacture to a moisture contentof not more than 15 percent; smoothly machinedand d

35、ressed on all sides; free from sharp edgesand splinters; and sound and free by acceptedprocedures of visual inspection from shake, wane,compression failures, decay, or other irregularitiesexcept as hereinafter provided. Low-density woodshall not be used.To allow for normal variations in width and th

36、ick-ness which occur in surfacing lumber, on up tofive percent of the length of a part, the depth andthickness may be undersized a maximum of 1/64“when measured at a moisture content of 15 percent.Permissible irregularities as provided for in thisstandard are based on minimum dimensions. Whenoversiz

37、ed parts are used some deviations fromthose irregularities may be allowable.5.1.1.2 Compression Wood. Compression woodis found mostly in softwoods. Compression woodcommonly has a density somewhat higher than thatof normal wood but has somewhat lower stiffness andtensile strength for equivalent weigh

38、t. Compressionwood has high longitudinal shrinkage that frequentlycauses warping of long, slender structural memberssuch as ladder rails. This variant type of wood struc-ture, when of a damaging nature, can be readilyidentified, by competent and conscientious visualexamination during the grading and

39、 manufacturingprocess, by its relatively wide annual rings and largeproportion of latewood, which is darker and oftenreddish in color and commonly has a dull lifelesssurface appearance. Moreover, the dark latewoodmerges slowly with the earlywood of the same annualrings rather than being more sharply

40、 delineated. Theextent of compression woods effect on strength andwarping varies with the proportion of compressionwood in a cross section. For example, wide streaks ofreadily identifiable compression wood comprisingthe larger part of the annual rings in a piece of lumberare associated with more ser

41、iously adverse propertiesthan narrow streaks involving only a few annualrings, particularly when the latewood comprisesone-third or less of the ring widths in narrow streaks.American National Standard A14.1-20074The presence of microscopic levels of compressionwood is not uncommon in softwoods. The

42、use ofmagnifying equipment to search for such smallareas is not necessary. These small regions have nomeasurable effect on strength.5.1.1.3 Cross Grain. Cross grain is limited interms of its slope, which is defined as the distancealong the sides of the piece in which a deviationof the grain of 1 inc

43、h occurs. For example, crossgrain with a slope of one in 12 means that in adistance of 12 inches, the grain deviates one inchfrom the edge of the piece. The slope of grainshall be measured over a distance that will ensurethat the determination of the general slope of thegrain is consistent and is no

44、t influenced by shortlocal deviations which do not pass from surface tosurface on either the wide or narrow faces.When the grain direction differs between oppositefaces on edges, averaging is appropriate. A slopeof one in twenty shall be used for any surfacehaving that value or less.Local deviations

45、 of the grain from the generalslope in the piece are usually associated with aknot or other irregularity that may or may not bepresent in the piece. In addition to the limits ongeneral slope of grain, it is also desirable, inpieces of small cross section such as occur inladder parts, to limit the oc

46、currence of localdeviations, except for those which are associatedwith otherwise permitted irregularities appearingin the piece.5.1.1.4 Limited Irregularities. Black streaks inwestern hemlock shall not be considered an irregu-larity. However, openings or chambers associatedwith black streaks, when p

47、resent in the part, shallbe limited as specified for pitch and bark pockets.5.1.2 Permissible Irregularities in Side Rails andBack Legs.5.1.2.1 Cross Grain. The general slope of the grainin side rails and back legs shall not be steeper thanone in 12, except for ladders under 10 feet inlength and hav

48、ing flat steps for treads, in whichthe general slope of the grain shall not be steeperthan one in 10. The slope of the grain in areas oflocal grain deviation shall be limited as abovewhen occurring on the narrow face or in the outerone-fourth of the width of the wide face. Localareas of grain deviat

49、ion within the center half ofthe width of the wide face may be permitted tocontain a grain slope as steep as one in eight.Local deviations of grain associated with other-wise permissible irregularities shall be permitted.5.1.2.2 Knots. Knots shall not appear in a narrowface of a side rail or back leg. Knots, if tight andsound and less than 1/2 inch in diameter, shall bepermitted on the wide face provided no part ofthe knot is within 1/2 inch from either edge andknots are not more frequent than one in any threefeet of length.5.1.2.3 Pitch and Bark Pockets. Pitch and barkpockets in side