This standard specifies the safety requirements and precautions applicable to fixed ladders with single or double columns, with or without fall protection devices. This standard applies to fixed ladders used as access to machines. The ladder can be: - a component of the machine; - fixed to the machine; - fixed to other components near the machine. For the selection of ladders used as access to machines, see GB 17888.1. GB 17888.4-1999 Mechanical safety - Fixed facilities for access to machines and industrial equipment - Part 4: Fixed straight ladders GB17888.4-1999 Standard download decompression password: www.bzxz.net

GB 17888. 4--1999
This standard is equivalent to ISO/DIS14122-4:1996 in terms of technical content. The main differences from ISO/DIS14122-4 are as follows:
1. The introduction of ISO/DIS14122-4 is cancelled because it is only for the European Union. 2. For the European standards or draft standards cited in ISO/DIS 14122-4, those with corresponding national standards or those under development have been changed to reference the corresponding national standards. For those without corresponding national standards or those that have not yet been developed, only EN353-1 that is actually used in the text is retained, and the rest that are not mentioned in the text are not listed. This standard is the fourth part of the series of standards "Fixed facilities for access to machines and industrial equipment". This series of standards consists of four standards, and the other three standards are:
Part 1: Selection of fixed facilities for access between two levels. Part 2: Working platforms and passages.
Part 3: Stairs, steps and guardrails.
Appendix A of this standard is a reminder appendix.
This standard is proposed by the State Machinery Industry Bureau. This standard is under the jurisdiction of the National Machinery Safety Standardization Technical Committee. The responsible drafting unit of this standard: Mechanical Science Research Institute. Participating drafting units: Jilin Labor Protection Science Research Institute, China Standardization and Information Classification and Coding Research Institute.
Main drafters of this standard: Ma Zhi, Shi Junwei, Xiao Jianmin, Zhang Mingxu, Li Qin, Yongcai, Xiao Wei. 71
GB 17888.4—1999
ISO Foreword
This standard was developed by CEN/TC114 Working Group 17. It is the fourth part of the standard "Fixed facilities for safe access to machines and industrial equipment". The several parts of this standard are: Part 1: Selection of fixed facilities for access between two levels. Part 2: Working platforms and passages.
Part 3: Stairs, steps and guardrails.
Part 4: Fixed ladders.
The use of non-metallic materials (wood, composite materials, etc.) does not change the application of this standard. All the provisions of this standard shall be observed in all cases.
National Standard of the People's Republic of China
Safety of machinery
Fixed means of access to machines and industrial plants-Part 4: Fixed ladders
Safety of machinery--
Permanent means of access to machines and industrial plants-Part 4:fixed ladders
1 Scope
GB 17888. 4 -- 1999
This standard specifies the safety requirements and precautions applicable to fixed ladders with single or double columns with or without fall protection devices. This standard applies to fixed ladders used as access to machines. The ladder can be: ... a component of the machine
- fixed to the machine;
- fixed to other components near the machine. For the choice of ladders as access to the machine, see GB17888.1. 2 Reference standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB12265.1—1997 Machinery safety Safety distance to prevent upper limbs from touching dangerous areas GB12265.3-1997 Machinery safety Minimum distance to avoid squeezing of various parts of the human body G3/T 15706.1-1995 Basic concepts and general principles for machinery safety Part 1: Basic terms, methodology GB/T15706.2-1995 Basic concepts and general principles for machinery safety Part 2: Technical principles and specifications Rules for drafting and expressing safety standards
GB/T16755--1997 Machinery safety
GB/T 16856--1997
Machinery safety
GB 17888. 1—1999
GB 17888. 2--1999
Principles of risk assessment
Safe access to fixed facilities for machinery and industrial equipment Part 1: Selection of fixed facilities for access between two levels
Safe access to fixed facilities for machinery and industrial equipment Part 2: Working platforms and passages GB17888.3-1999#
Safe access to fixed facilities for machinery and industrial equipment Part 3: Stairs, steps and guardrails GB/T17889.2-1999 Ladders Part 2: Requirements, tests and marking 3 Definitions
In addition to the relevant definitions in GB/T15706.1, this standard also uses the following definitions. Examples of the main definitions used in this standard are shown in Figures 1, 2, 3 and 4.
3.1 Fixed ladders
Approved by the State Administration of Quality and Technical Supervision on October 18, 1999, and implemented on October 1, 2000
GB 17888. 4 -1999
A fixed ladder is a stable access to an elevated working position. It has rungs firmly fixed on double or single columns and an inclination angle of 75° to 90°.
3.2 Fixed ladders with two uprightsFixed ladders with each rung fixed between two columns. The load is borne by two columns (see Figure 2). 3.3 Fixed ladders with one uprightFixed ladders with each rung fixed on both sides of the column. Only one column bears the load (see Figure 3). 3.4 Ladder flight
The continuous part of a fixed vertical ladder:
a) for a ladder without a platform, it is located between the departure level and the arrival level; or b) between the departure level and the nearest platform and between the arrival level and the nearest platform respectively; or c) between the rest platforms (see Figure 1). 3.5 Climbing height H of a fixed ladders The vertical distance between the walking surface of the entire ladder top arrival surface and the walking surface of the ladder bottom departure surface (see Figure 1. 3.6 Height h of the ladder flight The vertical distance between the starting plane and the end plane of the ladder flight. 3.7 Anti-fall devices Anti-fall devices are technical facilities to prevent or reduce the risk of people falling from fixed ladders. Commonly used anti-fall devices are:
- safety cages,
- a fall arrester on a rigid anchor rail.
3.8 Safety cages safety cages
A modular frame used to limit the risk of people falling from ladders (see Figure 2). 3.9 Guided type fall arresters on rigid anchorage line (fall arrester A protective device fixed to a ladder that is used in conjunction with the personal protective equipment that must be worn by everyone before using a ladder. When the user is connected to the protective equipment fixed to the ladder, the equipment can prevent a fall in the event of a loss of balance (see Figure 4). 3.10 arrival level
The plane above the ladder or intermediate platform to which a person can walk after ascending. 3.11 departure level The plane below the ladder or intermediate platform from which a person begins to climb a fixed vertical ladder. 3.12 intermediate platform The platform through which a ladder user can reach the platform of the adjacent staircase of a staggered staircase (see Figure 1). 3.13 rest platform
An area equipped with the required protective equipment and designed to allow ladder users to rest before climbing up or descending to the ground. These rest platforms are equipped with doors and should be sized to allow emergency intervention measures (see Figure 1). 3.14 access platform platform
A platform arranged on the arrival or departure surface for people to walk on. 3.15 trapdoor
A normally closed device that can be opened to allow people to enter through the platform or other similar horizontal structure. 3.16 lockout (intruder-proof protection) A device that prevents access to a fixed ladder. 74
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GB 17888. 4--1999
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①Fixed bracket
②Tread
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③Kick board
③Slanted handrailwww.bzxz.net
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B--Safety cage
GB 17888. 4 -- 1999
Figure 2 Fixed vertical ladder with safety cage
①Column ②Treads?Anti-slip protection device ①Fixed point a) Treads on both sides are at the same height
Figure 3 Single-column ladder
b) Treads on both sides are staggered
①Rigid anchor rail
②Fall arrester
?Connector
①Column
?Treads
4 Safety requirements and/or facilities
4.1 General requirements
GB17888.4—1999
Figure 4 Rigid anchor rail fall arrester
The selection of materials, dimensions and construction mode of each component shall meet the safety requirements of this standard and the various test data specified in Chapter 5.
Access to the machine shall be calibrated under the same installation conditions as the reference machine, and if necessary, environmental corrosion, vibration damage to the structure, aging of materials, etc. shall also be taken into account. All parts that may come into contact with the user shall be designed so as not to cause harm to the person (e.g. avoid sharp corners, welding burrs or rough edges, etc.), and opening or closing movable parts (doors, locks) shall not cause further danger to the person using the ladder or people around the ladder (e.g. shearing or accidental falling).
All joints, hinges, supports, supports and mountings shall be ensured to be assembled sufficiently firmly and stably to ensure the safety of the user under normal conditions of use.
4.2 Strength of fixed vertical ladders
4.2.1 General requirements
The structure of the ladder, platform and safety cage (when installed) shall be able to withstand the expected loads specified below: 4.2.1.1 Ladder components
The components of the ladder shall meet the requirements of GB17889.2. The maximum deflection shall not exceed 30 mm (see 5.3.1). In the case of a single-post ladder, the deflection of the ladder shall not exceed 20 mm when a torsion test with a test force of 400 N is used instead of a lateral bending test (see Figure 16). For rungs, the load is applied over a length of 100 mm close to the lateral anti-slip device. The residual deflection of the rung shall not exceed 3 % of the rung length (see 5.3.2).
4.2.1.2 Safety cage
The safety cage is considered to meet the requirements if the permanent deformation is not greater than 50 mm under a vertical load of 1000 N and not greater than 10 mm under a horizontal load of 300 N (see 5.2). 4.2.1.3 Fixed vertical ladders equipped with fall arresters Fixed vertical ladders equipped with fall arresters on rigid anchor rails shall be able to support the load in the event that the ladder user falls downwards and is arrested by the fall arrester (see Chapter 5).
4.2.2 Connecting elements
GB 17888. 4 ---1999
Connecting elements such as various joints, supports, hinges, supports and mountings shall be assembled sufficiently firmly and stably to ensure the safety of users under normal use conditions (see Chapter 5). For fixed vertical ladders equipped with fall arresters, each connecting element shall be able to withstand the stress generated by the fall arrester intercepting a person falling downward. 4.2.3 Platforms
See GB 17888. 2.
4.3 Installation conditions for fall prevention devices
In the following cases, the ladder shall be equipped with a fall prevention device: a) The height of the ladder section is above 3000mm;
b) The height of the ladder is equal to or less than 3000mm, but there is a risk of falling at the starting point. NOTE: A fall risk is considered to exist when the distance from the centre of the ladder to the unprotected edge of the platform (or similar structure) is less than 3 000 mm (see Figure 7). 4.4 Ladders
The essential dimensions of the ladder shall be as shown in Figures 5 and 6. 78
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Figure 5 Main dimensions of ladder and safety cage
①See 4.4.1.2
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②See 4.4.1.2 and Figure 8a
GB17888.41999
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③See 4.7 and Figure 11250
Figure 6 Main dimensions of single-column fixed vertical ladderFigure 7 Starting surface at the bottom of the ladder
4.4.1 Position of the rungs
4.4.1.1 Spacing between two rungs
GB 17888. 41999
The spacing between two adjacent rungs should be consistent and should be between 250 and 300 mm. 4.4.1.2 Distance between the rungs and the starting surface and the arrival surface It is recommended that the distance between the walking surface of the starting surface and the first rung be equal to the distance between adjacent rungs. In the case of movable machinery used on uneven ground, the distance between the walking surface of the departure side and the first step bar can be varied to a maximum of 400 mm. The top step bar should be positioned at the same level as the walking surface of the arrival side. The maximum deviation is 150 mm (see Figure 8a). Walking surface of the arrival surface
②Tolerance..50mm
a) Position of the uppermost step
①Supporting surface
b1Recommended installation
①No sharp edges to injure hands
b2Installation for special use only
b)Polygonal step structure
c)U-shaped step structure
Figure 8 Position and structure of step
4.4.1.3Step position of single-column fixed ladder GB17888.4-1999
Steps on both sides of the column should be at the same level or staggered at equal distances (see Figure 6). 4.4.1.4Polygonal step position
The step depth of the polygonal step is at least 20mm. The step edge of the polygonal step is only processed into a flat surface for special use (see Figure 8b).
4.4.2 Length of rungs
4.4.2.1 Length of rungs for fixed vertical ladders with two columns The length of the rungs shall be between 400 and 600 mm (see Figure 5). However, where the close environment does not allow them to be 400 mm long, a shorter length between 300 and 400 mm is permissible. In such cases, a check should be made beforehand to see if a favourable position for the ladder can be found that allows a rung length of 400 mm or more. 4.4.2.2 Length of rungs for fixed vertical ladders with two columns and rigid anchor rail for fall arrester The length of the rungs between the rigid anchor rail for fall arrester and the column shall be at least 150 mm (see Figure 9). @
D Rigid anchor rail
② Column
③ Tread
≥150
Figure 9 Length of the rung of the double-column enclosed vertical ladder and the rigid anchor rail of the fall arrester 4.4.2.3 The length of the rung between the column and the anti-slip device of the single-column fixed vertical ladder should be between 150 and 250 mm, and the thickness of the column should be less than 80 mm (see Figure 6).
4.4.3 Cross section of the rung
The diameter of the rung should be between 25 and 35 mm, and the width of the tread of the polygonal rung should be at least 20 mm. The cross section of the rung should be easy to grasp by hand.
4.4.4 Surface of the rung
The surface of the rung should not cause damage, especially to the hands (see Figure 8c). The surface of the rung should be able to prevent the feet (shoe soles) from slipping. When the risk of slipping is increased due to environmental factors (such as oil, etc.), special anti-slip measures need to be provided.
4.4.5 Anti-slip devices
The ends of the rungs of a single-column fixed straight ladder should be equipped with protective devices to prevent the rungs from sliding sideways. These anti-slip protective devices should be at least 20mm high (see A in Figure 6). 4.4.6 Distance between ladder and surrounding fixed parts The distance between ladder and surrounding fixed parts shall be at least 650 mm at the front of the ladder, at least 200 mm at the rear side of the rungs and at least 150 mm at the rear side of the rungs in case of intermittent obstacles (see Figures 5 and 6). 4.5 Safety cage
The safety cage shall start between 2200 and 3000 mm above the departure plane. On the lower access side of the safety cage, there shall be no elements that hinder access to the ladder. At the arrival plane, the safety cage shall extend to the height of the arrival plane guardrail (see Figure 5). The diameter of the safety cage in the hoop shall be between 700 and 800 mm (see D in Figure 5). The distance from the rungs to the safety cage shall be between 700 and 800 mm.
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