GB/T 33579-2017 Safety of machinery - Control methods of hazardous energy - Lockout/Tagout
1 Scope
This standard specifies the requirements for hazardous energy control that may cause personal injury.
This standard also stipulates the protection steps, technology, design, methods and performance indicators for controlling the accidental release ) of hazardous energy, so as to avoid personal injury.
This standard is applicable to the design, manufacture, installation, construction, repair, adjustment, inspection, dredging, setting, trouble shooting, testing, cleaning, disassembly, maintenance and so on during the whole life cycle of the machine.
This standard is not applicable to the maintenance of electrical equipment whose power supply are connected by wires and plugs, and the plugging and unplugging of power plug are controlled by the maintenance personnel only. In this case, unplugging the power plug can control the possible injury caused by accidental power-on or accidental start-up of the machine.
This standard is also not applicable to pressure pipeline transmission and distribution systems for water, steam, natural gas or petroleum products, etc.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB 5226.1-2008 Electrical safety of machinery - Electrical equipment of machines - Part 1: General requirements
GB/T 15706-2012 Safety of machinery - General principles for design - Risk assessment and risk reduction
GB/ T19876 Safety of machinery - Positioning of safeguards with respect to the approach speeds of parts of the human body
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 5226.1-2008 and GB/T 15706-2012 as well as the following apply.
3.1
alarm
reminding people of potential hazards by auditory or visual means, such as machine start-up, movement, failure or malfunction
3.2
authorized individual
individual assigned to perform hazardous energy control
3.3
control circuit
circuit used to start or interrupt the energy of the machine, or circuit of the control device or system used to control the performance of the machine without directly interrupting the energy
Note: control circuit may be hydraulic, pneumatic, electrical and electromechanical.
3.4
control reliability
ability of a system to prevent or stop hazardous movement when a single component in a device or system fails
3.5
control system
sensors, manual input and mode selection elements, interlocking and voting circuits and output elements provided for machine operating devices or mechanisms
3.6
de-energized
the case that when all energy sources are cut off, there is no remaining energy or stored energy
3.7
energized
the case that energy is connected or surplus energy or stored energy is left
3.8
energy isolating device
mechanical device that physically prevent energy transmission or release, such as:
- manually operated circuit breaker, cutoff switch and manual switch, through which all live wire connections can be disconnected at the same time;
- shut-off valve;
- stopper;
- other similar devices for blocking or isolating energy.
3.9
hazardous energy
any energy that may cause personal injury, including electrical, mechanical, hydraulic, pneumatic, chemical, thermal, potential energy, etc.
3.10
lockout device
an active way (such as a lock), which can ensure that the energy isolating device is in a position preventing the machine from being energized
3.11
lockout/tagout
behavior that the lock/tag is put on the energy isolating device according to the established procedure to indicate that the energy isolating device shall not be operated until the lock/tag is removed according to the established procedure
Note: The term "lockout/tagout" may indicate individual use of lockout or tagout device or simultaneous use of them.
3.12
tagout device
conspicuous warning device, such as a tag, that can be firmly fixed on the energy isolating device to indicate that the machine under control cannot be operated before the tagout device is removed
3.13
user
entity that uses machinery that conforms to the definition in 3.1 in GB/T 15706-2012 and is responsible for personnel related to hazardous energy control
4 Responsibilities
4.1 Manufacturer’s responsibilities
Manufacturers shall consider the control of hazardous energy in the process of designing, manufacturing and installing machines, so that users can effectively control hazardous energy during the whole life cycle of the machine (see Clause 1).
4.2 User’s responsibilities
The user shall, in accordance with the relevant provisions of this standard, develop an effective scheme to protect the personnel engaged in relevant activities during the whole life cycle of the machine (see Clause 1) from hazardous energy.
Note: Due to the nature of the work, users can also be manufacturers in some cases.
4.3 Responsibilities of authorized individual
Authorized individual shall abide by the scheme, procedures and training provided by users for implementing hazardous energy control.
5 Design
5.1 Requirements on manufacturer
5.1.1 General requirements
The design, manufacture and installation of machine shall be easy for users to implement the control methods specified in this standard. Any modification affecting energy isolation shall conform to this standard. Risk assessment shall be performed in the design stage of machine to determine the demand and design margin for energy isolating devices and systems. See Clause 5 of GB/T 15706-2012 for the risk assessment procedure.
5.1.2 Exposure minimization
The machine designed by manufacturer shall be reliable to ensure that there is no need for too much intervention. The design of machine shall avoid personnel engaged in routine and repeated maintenance and maintenance being exposed to hazardous energy.
Note: this can be achieved by placing the controller outside the hazardous area, adding controllers at appropriate positions, providing external lubrication points or providing protective devices.
5.1.3 Partial energization
For those functions that require partial energization, the manufacturer shall conduct risk assessment according to Clause 5 of GB/T15706-2012 to determine the safest way to enter the machine. When it is necessary to keep partial energization (for example, to clamp workpieces, save information, keep heat or provide local lighting), other control methods shall be provided to ensure the safety of personnel.
5.2 Energy isolating device
5.2.1 General requirements
In order to meet the requirements of 6.3, the design, manufacture and installation of the machine shall consider the energy isolating device based on its use. Energy isolating device shall be able to control and/or dissipate hazardous energy. Energy isolating device should be an integral part of the machine.
If the device is not integrated into the machine, the manufacturer shall recommend the type and installation location of the energy isolating device in the installation instructions.
5.2.2 Location
Energy isolating device shall be installed at an easily accessible location. If feasible, it shall be located in a position where it is easy to use the locking device during repair and maintenance.
Note: it is best to locate the energy isolating device outside hazardous are, and be in an adjacent walkable area, at a height easy for operation (i.e., not high, not on the ladder, and not under the machine).
5.2.3 Identification
All energy isolating devices shall be fully identified or marked unless their location and arrangement make their use clear. The designation shall include:
