The structure of safety standards in the field of machinery is as follows:
a) type-A standards (basic safety standards) giving basic concepts, principles for design, and general aspects that can be applied to all machinery;
b) type-B standards (generic safety standards) dealing with one safety aspect or one or more type(s) of safeguard that can be used across a wide range of machinery;
——type-B1 standards on particular safety aspects (e.g. safety distances, surface temperature, noise);
——type-B2 standards on safeguards (e.g. two-hand controls, interlocking devices, pressure-sensitive devices, guards);
c) type-C standards (machine safety standards) dealing with detailed safety requirements for a particular machine or group of machines.
This standard is a type-B2 standard as stated in GB/T 15706.
This standard is particularly relevant to the following parties concerned with mechanical safety:
——Machine manufacturer;
——Health and safety agency.
Other parties concerned affected by the mechanical safety level are:
——Machine user;
——Machine owner;
——Service provider;
——Consumer (for machinery intended to be used by consumers).
All the above parties concerned may participate in the drafting of this standard.
In addition, this standard is intended to be used by standardization organizations drafting type-C standards.
The requirements of this standard may be supplemented or modified by a type-C standard.
For machines that are covered by the scope of a type-C standard and that have been designed and built according to the requirements of that standard, the requirements of that type-C standard take precedence.
Guards provide a risk reduction for both protection against unintended access and against ejected parts and substances. The guarding can also give protection against others hazards, e.g. noise, fire, biological hazards, and radiation.
Safety of machinery—Guards—
General requirements for the design and construction of fixed and movable guards
1 Scope
This standard specifies general requirements for the design, construction, and selection of guards provided to protect persons from mechanical hazards.
This standard indicates other hazards that can influence the design and construction of guards.
This standard applies to guards for machinery which will be manufactured after it is published.
The requirements are applicable if fixed and movable guards are used.
This standard does not cover inter locking devices. These are covered in ISO 14119.
This standard does not provide requirements for special systems relating specificality to mobility such as ROPS (roll-over protective structures), FOPS (falIing-object protective structures), and TOPS (tip over protective structures) or to the ability of machinery to lift loads.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated reference, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 5226.1-2008 Safety of machinery—Electrical equipment of machines—Part 1: General requirements (IEC 60204-1: 2005, IDT)
GB/T 15706-2012 Safety of machinery—General principles for design—Risk assessment and risk reduction (ISO 12100: 2010, IDT)
ISO 13855 Safety of machinery—Positioning of safeguards with respect to the approach speeds of parts of the human body
ISO 13857 Safety of machinery Safety distances to prevent hazard zones being reached by upper and lower limbs
ISO 14119 Safety of machinery Interlocking devices associated with guards—Principles for design and selection
ISO 14123-1 Safety of machinery Reduction of risks to health from hazardous substances emitted by machinery—Part 1: Principles and specifications for machinery manufacturers
ISO 14159 Safety of machinery—Hygiene requirements for the design of machinery
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 15706-2012 and the following apply.
3.1
guard
physical barrier, designed as part of the machine, to provide protection
Note 1: A guard may act either:
——alone, in which case it is only effective when "closed" (for a movable guard) or "securely held in place" (for a fixed guard).
——in conjunction with an interlocking device with or without guard locking, in which case protection is ensured whatever the position of the guard.
Note 2: Depending on its construction, a guard may be described as, for example, casing, shield, cover, screen, door, enclosing guard.
Note 3: The terms for types of guards are defined in GB/T 15706-2012, 3.27.1 to 3.27.6. See aIso GB/T 15706-2012, 6.3.3.2 for types of guards and their requirements.
[GB/T 15706-2012, Definition 3.27]
3.2
fixed guard
guard affixed in such a manner (for example, by screws, nuts, and welding) that it can only be opened or removed by the use of tools or by destruction of the means by which the guard is affixed
[GB/T 15706-2012, Definition 3.27.1]
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3.2.1
enclosing guard
guard which pr e vents access to the hazard zone from all sides
Note: see Figure 1.
Figure 1 Example of an enclosing guard totally preventing access to transmission machinery
3.2.2
distance guard
guard which does not completely enclose a hazard zone, but which prevents or reduces access by virtue of its dimensions and its distance from the hazard zone, for example perimeter fence or tunnel guard
Note 1: A distance guard can be partially or fully surrounding.
Note 2: See Figures 2 and 3.
Figure 2 Example of a distance guard
Figure 3 Example of a distance guard: tunnel guard providing protection at machine feed or discharge area
3.3
movable guard
guard which can be opened without the use of tools
[GB/T 15706-2012, Definition 3.27.2]
3.3.1
power-operated guard
movable guard that is operated with the assistance of power from a source other than persons or gravity
3.3.2
self-closing guard
automatically adjustable guard
movable guard operated by a machine element (e.g. moving table) or by the workpiece or a part of the machining jig, so that it allows the workpiece (and the jig) to pass and then automatically returns (by means of gravity, a spring, other external to the closed position as soon as the workpiece has vacated the opening through which it has been allowed to pass
Note: See Figure 4.
Figure 4 Example of a self-closing guard
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3.4
adjustable guard
guard which is adjustable as a whole or which incorporates adjustable part(s)
[GB/T 15706-2012, Definition 3.27.3]
3.4.1
manually adjustable guard
adjustable guard where the adjustment is made manually and the adjustment remains fixed during a particular operation
Note: See Figure 5.
Figure 5 Example of an adjustable guard for a radial or pedestal drilling machine
3.5
interlocking guard
guard associated with an interlocking device so that, together with the control system of the machine, the following functions are performed:
——the hazardous machine functions "covered" by the guard cannot operate until the guard is closed;
——if the guard is opened while hazardous machine functions are operating, a stop command is given;
——when the guard is closed, the hazardous machine functions "covered" by the guard can operate. The closure of the guard does not, by itself, start the hazardous machine functions.
Note 1: See Figures 6 and 7.
Note 2: See ISO 14119 about interlocking devices.
[GB/T 15706-2012, Definition 3.27.4]
Figure 6 Example of interlocking hinge guard (when closed, the danger zone is closed)
Figure 7 Example of interlocking sliding guards
3.5.1
interlocking guard with a start function
control guard
special form of interlocking guard which, once it has reached its closed position, gives a command to initiate the hazardous machine function(s) without the use of a separate start control
Note: GB/T 15706-2012, 6.3.3.2.5, gives detailed provisions regarding the conditions of use for a control guard (see also 5.3.14).
[GB/T 15706-2012, Definition 3.27.6]
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3.5.2
interlocking guard with guard locking
guard associated with an interlocking device and a guard locking device so that, together with the control system of the machine, the following functions are performed:
——the hazardous machine functions "covered" by the guard cannot operate untiI the guard is closed and Iocked;
——the guard remains closed and Iocked until the risk due to the hazardous machine functions "covered” by the guard has disappeared;
——when the guard is closed and locked, the hazardous machine functions "covered" by the guard can operate. The closure and Iocking of the guard do not, by themselves, start the hazardous machine functions.
Note 1: See ISO 14119 about interlocking devices.
Note 2: See Figure 8.
[GB/T 15706-2012, Definition 3.27.5]
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Terms and definitions
4 Risk assessment
5 General requirements for the design and construction of guards
5.1 Machine aspects
5.2 Human aspects
5.3 Guard design and construction aspects
5.4 Materials, rigidity, and impact requirements
5.5 Containment
5.6 Resistance to corrosion
5.7 Resistance to microorganisms
5.8 Non-toxicity
5.9 Machine viewing
5.10 Transparency
5.11 Shadows and stroboscopic effects
5.12 Electrostatic properties
5.13 Guards with electrically conductive parts
5.14 Thermal stability
5.15 Fire and flammability
5.16 Noise and vibration reduction
5.17 Radiation protection
5.18 Climbing
5.19 Retained fastenings
5.20 Vibration resistance
5.21 Warning signs
5.22 Color
5.23 Appearance
6 Selection of types of guards
6.1 General
6.2 Combination of different guards or of guards with other devices
6.3 Selection of guards according to the number and size of the hazards
6.4 Selection of guards according to the nature and frequency of access required
7 Verification of the safety requirements for guards
7.1 General
7.2 Verification and validation methods
7.3 Required verification and validation
8 Information for use
8.1 General
8.2 Guard hazards
8.3 Installation
8.4 Operation
8.5 Removal of guards
8.6 Inspection and maintenance
Annex A (Informative) Example of retained fastening
Annex B (Informative) Example of projectile test method for mechanically testing guards
Annex C (Informative) Example of pendulum test method for mechanically testing guards
Bibliography
