1、ANSI-ASC A14.11-2018American National StandardsAmerican National Standard Safety Requirements for StepstoolsANSI-ASCnullA14.11-2018American National Standard Safety Requirements for StepstoolsSecretariatAmerican Ladder Institute Approved June 22, 2018American National Standards Institute, Inc.Free l
2、adder safety resources are available from the American Ladder Institute at www.laddersafety.org. A Multimedia Training Program provides guidance on safe ladder selection, use and care at www.laddersafetytraining.org.For information on possible errata sheets and other ANSI-ASC A14 Standards please re
3、fer to the ALI website located at:www.americanladderinstitute.orgiAn American National Standard implies a consensus of those substantially concerned with its scope and provisions. An American National Standard is intended as a guide to aid the manufacturer, the consumer, and the general public. The
4、existence of an American National Standard does not in any respect preclude anyone, whether they have approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. American National Standards are subject to period
5、ic review and users are cautioned to obtain the latest editions and errata sheets.The American National Standards Institute does not develop standards and will in no circumstances give an interpretation of any American National Standard. Moreover, no persons shall have the right or authority to issu
6、e an interpretation of an American National Standard in the name of the American National Standards Institute.CAUTION NOTICE: This American National Standard may be revised or withdrawn at anytime. The procedures of the American National Standards Institute require that action be taken to reaffirm,
7、revise, or withdraw this standard no later than five years from the date of publication. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute.Published byAmerican Ladder Institute 330 N. Wabash Aven
8、ue, Suite 2000, Chicago, IL 60611Copyright by ANSI Accredited Standards Committee (ASC) A14 All rights reserved.No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior written permission of the publisher.Printed in the United State
9、s of AmericaAmerican National StandardiiForeword(This foreword is not part of the American National Standard A14.11-2018)This standard on Stepstools is one of the many American National Standards prepared under the ANSI Accredited Standards Committee on Safety in Construction, Care, and Use of Ladde
10、rs. A14 Subcommittees that report to the A14 Standards committee have developed the following A14 Standards: A14.1 Portable Wood Ladders; A14.2 Portable Metal Ladders; A14.3 Fixed Ladders; A14.4 Job-made Ladders; A14.5 Portable Reinforced Plastic Ladders; A14.7 Mobile Ladder Stands, A14.8 Ladder Acc
11、essories and A14.9 Disappearing Attic Stairways. This standard for Stepstools was prepared under the supervision of the American National Standards A14 Accredited Standards on Safety in Construction, Care, and Use of Portable Ladders. Prior to the release of this standard, wood, aluminum and fibergl
12、ass ladder-type stepstools were covered by ANSI A14.1, 14.2 usually joined by rungs, bars or other cross bracing to form the back section. The back section is typically not designed for climbing or standing unless specified by the manufacturer. Dead Load. A stationary load statically applied using s
13、olid weights or other unchanging downwardly applied force to simulate the effect of gravity.Duty Rating. The combination of factors, including, but not limited to, stepstool type and design features, which imply service capability.American National Standard A14.11-20183Check. A separation of the woo
14、d along the fiber direction that usually extends across the rings of annual growth, commonly resulting from stresses set up in the wood during seasoning.Compression Failure. A deformation (buckling) of the fibers due to excessive compression along the grain. This deformation may appear as a wrinkle
15、across the surface. In some cases, compression failures may be present but not visible as wrinkles; in such cases they are often indicated by “fiber breakage” on end grain surfaces.Compression Wood. An aberrant (abnormal) and highly variable type of wood structure occurring in softwood species (See
16、5.4.5.2 for more details).Cross Grain (Slope of Grain). The deviation of the general wood fiber direction from the center axis of the cross section of the piece. Slope is measured along the edges or on the surfaces of the piece using straight edges and is done visually on each part.Decay. The disint
17、egration of wood due to the action of wood-destroying fungi; also known as dote and rot.Knot. A portion of a branch or limb embedded in the tree and cut through in the process of lumber manufacture. It is classified according to size, quality, occurrence, and location in the cross section of a piece
18、. The size of the knot is determined by its average diameter on the surface of the piece.Low-density Wood. Wood that is exceptionally light in weight and usually deficient in strength properties for the species. In softwood species, low density is frequently indicated by exceptionally wide, or somet
19、imes by extremely narrow, rings, and generally a low proportion of latewood. On the other hand, low-density hardwood, at least in ring-porous species, is most commonly indicated by excessively narrow annual rings in which the earlywood portion predominates.Pitch Pocket. An opening extending parallel
20、 to the annual growth rings that contains, or that has contained, either solid or liquid pitch.Shake. A separation along the grain, occurring most often between the rings of annual growth.Split. A separation of the wood parallel to the fiber direction due to tearing apart of the wood fibers normally
21、 caused by external forces.Tension Wood. A characteristic of hardwoods created by tensile stresses during growth (usually associated with large branches). These regions are noted by fuzzy, torn grain on machined surfaces, which can result in strength losses and high shrinkage rates.Step/Platform Sur
22、faces. The usable areas on which a person may place their feet to support their weight while using a stepstool. Stepstool. A self-supporting portable climbing device, 36 inches or less in height. Test Failure. Damage or visible weakening of the stepstool structure or a component, except where otherw
23、ise defined by the test protocol. Localized discoloration (stress whitening) of plastic parts without the presence of a fracture, as a result of testing is allowable.Test Load. The applied load used to determine compliance with performance (test) requirements.Through Crack. Permanent damage in a com
24、ponent of a product, which is clearly visible from both sides of the component (see Visual Damage) during either a period of test loading or post-test loading. Top Rail. A component extending above the platform level from one side to the other that may be used as a carry handle and/or support rail d
25、uring use. Top Rails may be of any height unless intended for aiding the user with support and balance for stabilizing themselves, in which case the vertical distance from the platform to the top of the top rail must be a minimum of 16 inches (see 5.1.3 and Table 1 for how this relates to appropriat
26、e platform size).Ultimate Failure. The collapse of the stepstool structure or, where applicable, a component thereof.Utility Shelf. A component permanently attached to a stepstool forming a horizontal surface designed to support containers, tools or other materials, but not the user.Visual Damage. D
27、amage evident by visual inspection, without the aid of tools or magnification.Visual Inspection. Inspection by the eye without recourse to any optical device except the observers prescription eyeglasses.Working load. The maximum applied load, including the weight of the user, materials, and tools th
28、at the stepstool is to support for the intended use.4.2 Wood SpecificWood Characteristics. Distinguishing features, the extent and number of which determine the quality of a piece of wood.Wood Irregularities. Natural characteristics in or on the wood that may lower its durability or strength.Bark Po
29、cket. An opening between annual growth rings that contain bark. Bark pockets appear as dark streaks on radial surfaces and as rounded areas on tangential surfaces.American National Standard A14.11-20184side-to-side within 1.0 degree of the stepstools support surface. Step/platform surfaces shall be
30、level front-to-back within 2.5 degrees of the stepstools support surface. The support surface-to-bottom step spacing shall be at least 6 inches but not greater than the nominal step-to-step/platform vertical spacing (plus tolerance). 5.1.3 Platform Size. Platform size shall comply with the dimension
31、s listed in Table 1, as measured using the guidelines of Figure 1a. The effective area of any platform shall be determined by its gross perimeter as demonstrated in Figure 1a. Reduced minimum platform size dimensions (as specified in Table 1) are permissible for stepstools having a top rail extendin
32、g a minimum of 16 inches vertically above the platform level, as measured from the top of the platform to the top of the top rail.5.1.4 Inside Clear Width. The inside clear width on any standing surface below the platform shall not be less than 10.5 inches per Figure 1b.5.1.5 Step Size. The minimum
33、front-to-back dimension of all steps below the platform shall be 3 inches at all points over a central width of 10.5-in. as shown in Fig. 1b. Step size outside of the 10.5-in. minimum may be less than 3 inches. For levels below the platform meant only as transitional steps (not for standing and work
34、ing from), the step depth of 3-in. is not required to be maintained over the full 10.5-in. opening, but shall be Truss Rod. Threaded metal component (typically on wooden stepstools) located directly beneath a step.Wane. Bark, or lack of wood, on the corner of a piece.5. Design Requirements5.1 Genera
35、lSpecific design and construction requirements are minimized in this standard because of the wide variety of materials and design possibilities. However, the design shall have such characteristics as to produce a stepstool of sufficient strength and stiffness to meet the requirements of this standar
36、d and shall produce a stepstool without structural defects or accident hazards such as sharp edges, burrs, and the like.5.1.1 Stepstool Size Limitation and Tolerance. The size of the stepstool shall be measured as the vertical distance from the surface of the platform to floor. The labeled height sh
37、all not exceed 36 inches. The actual height measured on any sample product shall be within a tolerance of +/- 0.5-in. of the labeled size. 5.1.2 Step, and Platform Spacing smoothly machined and dressed on all sides; free from sharp edges and splinters; and sound and free by accepted procedures of vi
38、sual inspection from shake, wane, compression failures, decay, or other irregularities except as hereinafter provided. Low-density wood shall not be used.To allow for normal variations in width and thickness which occur in surfacing lumber, on up to 5 percent of the length of a part, the depth and t
39、hickness may be undersized a maximum of 0.016-in. when measured at a moisture content of 15 percent. Permissible irregularities as provided for in this standard are based on minimum dimensions. When oversized parts are used some deviations from those irregularities may be allowable.5.4.5.2 Compressi
40、on Wood. Compression wood is found mostly in softwoods. Compression wood commonly has a somewhat higher density than that of normal wood but a somewhat lower stiffness and tensile strength for its weight. Compression wood has high longitudinal shrinkage that frequently causes warping of long, slende
41、r structural members such as rails of ladder-type stepstools. This variant type of wood structure, when of a damaging nature, can be readily identified by competent and conscientious visual examination, by its relatively wide annual rings and large portion of latewood, which is yellow-to-red in colo
42、r and commonly has a dull lifeless appearance. Moreover, the yellow-to-red latewood merges with earlywood of the same annual rings rather than being more sharply delineated as in many softwood species. The extent of compression woods effects on strength and warping varies with the proportion of comp
43、ression wood in a cross section. For example, wide streaks of readily identifiable compression wood comprising the larger part of the annual rings in a piece of lumber are associated with more seriously adverse properties than narrow streaks.5.4.5.3 Slope of Grain. In this context, the slope is a th
44、ree dimensional property and must be checked on 5.3 Metal PartsMetal components shall meet the testing requirements for the stepstool component parts and shall be of a material that is protected against corrosion unless it is inherently corrosion-resistant.5.4 Solid Wood Parts5.4.1 General. Stepstoo
45、ls made with wooden steps and wooden rails shall meet all load and stability criteria set forth in this standard for other material types. The wood components shall be finished smooth and have eased edges. All assembly shall be done with wood pieces at or below a moisture content of 15 percent. All
46、wood parts shall be visually inspected for unacceptable characteristics as described in the following. 5.4.2 Construction. Ladder-type (A-frame) stepstools with flat wooden steps shall use threaded truss rods or equivalent means to allow for periodic tightening of the stepstool during its useful lif
47、e as needed. Truss rods of at least 0.160-in. diameter shall be used. 5.4.3 Wood Species and Quality. This standard does not present a comprehensive list of possible species for use in stepstools. A list of common United States species is presented in Appendix B and may be used as a reference. A lar
48、ge number of imported species are available as well. Properties of both groups are available from publications of the U.S. Department of Agriculture Forest Products Laboratory. 5.4.4 Wood Specifications. The most widely used wood species for ladder-type stepstools is the southern yellow pine group.
49、Any species that has properties comparable to this group of woods and is of an acceptable grade may be used for stepstool construction. The strength of wood is directly related to density, or specific gravity. Southern yellow pine density ranges from 29 to 42 lbs./ft3on average. Wood with density in this range can be expected to meet all strength needs. Lower density woods, including some tropical species, can be used if components are sized appropriately. Hardwood species as well as softwoods can be used if they meet the density range and have no strength reducing factors present. Side ra
