In situ manufacture or assembly of work equipment and plant

The roles and responsibilities, and route to compliance with product supply legislation, can be complicated for plant and machinery "manufactured" in situ (such as automating an existing gate). This contrasts to the more straightforward situation for products which are produced complete in the traditional factory environment.

More than one person / organisation is likely to have been involved in the design, construction and installation of the various items of equipment and connections between them, for example with a complex assembly line. Various product supply legislation may apply to all or just to parts complex assemblies, such as a chemical processing facility which may comprise machinery, electrical equipment, pressure plant and equipment intended for use in potentially explosive atmospheres. What exact parts are in scope of particular legislation may be less obvious, for example where does the "machine", such as an agitator or pump, end when it forms part of a large installation such as a storage tank farm. There may also be important duties under other legislation (eg the Construction, Design and Management Regulations), and some significant parts (eg structural) may themselves be out of scope of specific product supply legislation, but will be captured as part of the final complete assembly.

This page briefly explores these issues, gives guidance on ways to ensure that safety and health are met, with the aim that harm to workers and others who may be affected can be avoided.

In situ manufacture

Some machinery, such as powered gates (eg when reusing the existing gate leaves), complex assembly lines (eg for processing and packaging products) and large industrial plant (eg a refinery or biomass power plant), will in effect be manufactured in situ from various components – see list below. The common element is the bringing together component parts, many of which have been manufactured by others, into a new complete piece of equipment / plant. Some of these component parts may be:

  • complete ready to use products (eg machinery) supplied with a Declaration of Conformity (DoC) and appropriately labelled and conformity marked
  • complete ready to use products without a DoC, because no specific product legislation applies
  • Partly Completed Machinery supplied with a Declaration of Incorporation (DoI) intended for incorporation into or assembled with other machinery, other partly completed machinery or equipment, thereby forming a machine
  • Safety Components or Interchangeable equipment (both as defined), and so supplied with a Declaration of Conformity and appropriately marked
  • components, including basic structural parts, without conformity marking, because no specific product legislation applies.

Manufacturing (ie the design and assembly of the various elements) in these cases may be undertaken by the:

  • plant / equipment operator themselves
  • a single "installing" contractor
  • a principal or "turnkey" contractor managing and coordinating the work of other installing sub-contractors and suppliers
  • the main product manufacturer.

Because these situations are often unique and frequently complex the roles and responsibilities of all parties in meeting legal obligations under all of the relevant product and national legislation need to be determined separately in each case. These issues are briefly explored in the following examples, starting with the simpler single machine, then considering assemblies of machines, and finally some of the issues surrounding large complex industrial plant.

Powered gates, doors and windows

Existing manually operated sliding or hinged gates may be modified by adding powered actuators. New powered gates may be assembled on site using a variety of component parts from different suppliers. In both cases, a new machine is being made in situ, and before being put into service it must be safe by design and construction, and in full conformity with all relevant requirements of the Supply of Machinery (Safety) Regulations 2008. This includes taking into account the gate's environment and the likely presence of people, especially vulnerable persons, such as children and the older / less able, who may be at risk from the gate. This risk may come from unintended uses, either as part of its intended purpose, or incidentally because of its location and proximity to the public. Serious and fatal injuries have occurred involving unsafe powered gates and a number of Safety Bulletins have been issued for both installers and users of such machinery.

The person responsible as the "manufacturer" will be whoever coordinates or undertakes the work of powering a gate. Normally this will be the installer, although it can be the main contractor who coordinates the roles of a number of sub-contractors, or even the premises owner or occupier if they do the work themselves or design the system and get a contractor to do the actual assembly work to this design. During gate commissioning, and before the gate is put into service, they must ensure the gate and any safety systems are set and configured / adjusted so that it is safe and the essential health and safety requirements of the Supply of Machinery (Safety) Regulations 2008 are met. This includes appropriately marking the gate, issuing a Declaration of Conformity and producing detailed instructions, and providing them to the gate owner / user. These instructions should include a description of the adjustment and maintenance operations that need be carried out by the gate owner to ensure the gate remains safe. It also should contain what needs to be followed in the event of accident or breakdown, especially where persons are trapped by the mechanism. Further information including industry codes of practice are available from the DHF.

Where a powered gate, door or window is fully manufactured and shipped from the factory as a complete product, even though it may be in kit form and require assembly / installation on site, this is not considered as in-situ manufacture. In these cases the product must, like any other complete machine, undergo conformity assessment and be appropriately marked and labelled, come with a Declaration of Conformity and comprehensive Instructions, including for installation and assembly. In addition to meeting the requirements of the Supply of Machinery (Safety) Regulations 2008, such factory made building construction products may also come within scope of the Construction Product Regulations. In this case the factory manufacturer takes full responsibility for the product's conformity assessment under all relevant product legislation, and whoever installs it takes responsibility for safe installation according to the manufacturer's instructions (as required by Section 3 or section 6(3) of the Health & Safety at Work etc Act 1974).

HSE Safety Alerts

Installing an agitator inside a tank

An agitator, consisting of just a motor and impeller but without guarding, intended for stirring the contents of a tank, may be placed on the market by its manufacturer as partly completed machinery intended for incorporation under a Declaration of Incorporation, (it must be accompanied by assembly instructions). Only when that agitator is installed with other equipment, such as inside a tank, is it able to function fully as a machine. At the point when the agitator is fitted on the tank and connected to a power source it will come into service and must then meet all relevant requirements of the Supply of Machinery (Safety) Regulations 2008, including appropriate marking and labelling. The person undertaking this work becomes the "machine" manufacturer and responsible for the safety and conformity of the complete machine assembly.

For the purposes of conformity assessment and the technical file a notional limit will exist as to where the "machine" stops and non-machinery pipework/tank continues. This will usually be fairly obvious and should for clarity be defined in the technical file in each case. For example, where the machine with its moving parts affects the entire tank clearly the area defined as "machinery" will be greater than if just mounted within external pipework on the side of a tank where there is no access to dangerous moving parts from within the tank. What matters is that risk has been controlled. But, if for example, a complete pump is fitted and only needs a simple connection to a tank's pipework, it may be considered as a machine in its own right and need to be appropriately marked and labelled by the pump manufacturer and come with its own Declaration of Conformity.

A similar situation may exist with other types of equipment such as pressure vessels or equipment for use in potentially explosive atmospheres when attached to or combined with other equipment or machinery. There will be notional limits to the extent of the pressure system or potentially explosive zone that need to be taken into account in the conformity assessment of these products.

Assemblies of machines

The Supply of Machinery (Safety) Regulations 2008 apply to assemblies of machines as well as to individual complete machines where they are:

  • assembled together to carry out a common function,
  • the constituent parts are functionally linked in such a way that each unit affects the operation of other units so that a risk assessment of the whole assembly is necessary, and
  • the constituent units have a common control system.

A group of machines that are connected to each other but where each machine functions independently of the others is not considered to be an assembly of machinery in the above sense.

The definition of assemblies of machinery does not cover a complete industrial plant consisting of a considerable number of machines, assemblies of machinery and other equipment originating from different manufacturers. However, for the application of the Supply of Machinery (Safety) Regulations 2008, such large installations can usually be divided into sections which may be considered as assemblies of machinery. For example, raw material unloading and reception equipment - processing equipment - packaging and loading equipment. In that case, any risks created by the interfaces with the other sections of the plant must be covered by the installation instructions. Other product supply legislation may also apply to other parts of industrial plant.

The person constituting an assembly of machinery is considered as the manufacturer of the assembly of machinery and is responsible for ensuring that the assembly as a whole complies with the health and safety requirements of the Supply of Machinery (Safety) Regulations 2008, including conformity marking. In some cases, the manufacturer of the assembly of machinery is also the manufacturer of the constituent units. However, more frequently, the constituent units are placed on the market by other manufacturers, either as complete machinery that could also operate independently or as partly completed machinery. If the units concerned are placed on the market as complete machinery they must bear the appropriate conformity marking and be accompanied by a Declaration of Conformity. If they are placed on the market as partly completed machinery, they must  be accompanied by a Declaration of Incorporation and assembly instructions.

Assemblies of machinery are subject to the Supply of Machinery (Safety) Regulations 2008 because their safety depends not just on the safe design and construction of their constituent units but also on the suitability of the units and critically the safety of the interfaces between them. The risk assessment to be carried out by the manufacturer of an assembly of machinery must therefore cover both the suitability of the constituent units for the safety of the assembly as a whole and the hazards resulting from the interfaces between constituent units (such as the need for extra guarding). It must also cover any hazards resulting from the assembly that are not covered by the Declaration of Conformity (for machinery) or the Declaration of Incorporation and the assembly instructions (for partly completed machinery) supplied by the manufacturers of the constituent units.

The Declaration of Conformity for complete machines and the Declaration of Incorporation and the assembly instructions for partly completed machinery incorporated into the assembly of machinery must be included in the technical file for the assembly of machinery. The technical file for the assembly of machinery must also document any modifications that have been made to the constituent units when incorporating them into the assembly. The responsibility of the person manufacturing the line does not extend to the design of the individual machines and partly complete machines, provided they have checked that:

  • they came with a Declaration of Conformity or Incorporation
  • adequate instructions for installation, use, maintenance, etc
  • were appropriately marked and labelled
  • and are free from obvious defects (eg no missing or damaged guards).

Assemblies comprising new and existing machinery

The Supply of Machinery (Safety) Regulations 2008 apply to machinery when it is first placed on the market and or put into service (where not placed on the market). This is, in general, new machinery. For machinery in service (used at work), the employer must ensure that the conformity and safety of the machinery is maintained throughout its working life (Regulation 10 of PUWER). In some cases, one or more of the constituent units of existing assemblies of machinery may be replaced by new units, or new units may be added to an existing assembly of machinery. The question arises as to whether an assembly of machinery comprising new and existing units is, as a whole, subject to the Supply of Machinery (Safety) Regulations 2008. It must be assessed on a case by case basis, with the priority that risks, existing and any new risks created by the modifications, are properly managed for health and safety. However, it is clear that where a new machine is added to an assembly you do not have to re-assess those other machines in the assembly which are not affected in any way.

Large complex industrial plant

A number of product legislation may apply alongside each other to all or parts of industrial plant. For example a chemical processing facility or biomass energy/heat generating plant may include:

  • machinery subject to the Supply of Machinery (Safety) Regulations 2008
  • electrical equipment, subject to the Electrical Equipment Safety Regulations 2016
  • pressure plant subject to the Pressure Equipment Safety Regulations 2016 and Simple Pressure Vessels Safety Regulations 2016  (and in some cases the Pressure Safety Systems Regulations 2000)
  • equipment intended for use in potentially explosive atmospheres (subject to the 2016 ATEX Regulations).

Different parts of a complex industrial plant may be in scope of none, one or several product supply legislation depending on the nature of the component parts and the hazards arising. It is only possible to give very general advice on these issues because each situation will be different and must be considered individually.

In addition to determining the "boundaries" of the application of any specific product legislation (eg where does the "machine" end when it is part of a large fixed plant installation), there will be a need to analyse, and record in the various technical documentation, the application of all relevant product legislation that may apply to the various constituent parts of the plant, particularly the interfaces between legislation.

Those involved in the design of such plant will need to liaise with each other to resolve these issues and ensure that the final assembled plant is safe and meets all relevant legislative requirements.

Furthermore, significant parts of industrial plant may be out of scope of any of the specific product supply legislation yet have a bearing on how this legislation is met. These will include the environmental landscape, buildings and structures. The design and layout of such "parts" may affect the classification of hazardous zones under DSEAR and therefore the selection of equipment supplied under ATEX for use in hazardous zones. There may also be important duties under national legislation (eg the Construction, Design and Management or Pressure Systems Regulations) which relate to the planning, design and construction of industrial plant.

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Updated: 2023-02-13