14 Industrial facilities Jolyon Drury and Ian Brebner The Jolyon Drury Consultancy advises on the design of production, distribution and storage systems and facilities. Ian Brebner is a partner of architecture practice Austin-Smith:Lord
KEY POINTS: Constant change is endemic Increasing demand for small units and starter accommodation
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Contents 1 Introduction 2 Classification of production building types 3 Adaptability 4 Working methods 5 Machine sizes 6 Outline specification of a typical multi-strategy factory 7 Non-production accommodation 8 Bibliography
1 INTRODUCTION 1.01 Industrial facilities An Industrial facilty is a building enclosure and site within which goods are manufactured, assembled, stored or shipped/transshipped. Manufacturing processes continually develop, improve and evolve, but have generally been classified as either: 1 A transformation of elemental raw materials into a finished product or material that requires further manufacturing to become a finished product (commonly referred to as Heavy Industry). These are typified by traditional industries, such as Steel manufacture, Chemical manufactfure, Refining Plants, etc. 2 An assembly process which integrates finished components into a finished product (commonly referred to as Light or Medium Industry). These are typified by Automotive manufacturing, White Goods manufacturing, Electronics Manufacturing, etc. A third category of Technology manufacturing is rapidly evolving from the development of artificial/assisted intelligence, communications and biotechnology. The intellectual capital required to sustain this third category is a step change from the more traditional light and heavy industries that have previously predominated in the developed economies. Developed economies are changing their manufacturing base to this third category as a means of generating added value to sustain the increasing income aspiration of their workforce and maintaining their global trading position. This category demands greater integration of further education and research with the actual manufacturing activity. It is generally recognised that clustering together research and manufacturing facilities produces a catalytic effect where the total output (physical or intellectual) can exceed the sum of the parts – even though they may be separate enterprises. This has significant implications on the nature of the enclosure which accommodates these new industrial facilities. 1.02 History of industrial facilities The history of industrial development has been one of the continual changes following improvements in production equipment,
management and techniques. The key stages of the development of manufacturing which have influenced the design and nature of industrial building have been: 1 Craft-based manufacture, where individuals or small groups of individuals created the finished product from elemental raw materials. The building which facilitated this were in the main, relatively small-scale workshops, or indeed, individuals dwellings. An industrial building typology was not generally identifiable. 2 Power-assisted manufacture, where production machines were powered rather than manually operated. Significantly, the use of power increased the capacity of the machine and allowed the subdivision of the production process, decreasing reliance on the skill of the individual. This, in turn, facilitated a greater concentration of manufacturing capacity in a single location. Early power systems relied on extended shaft drives with belt-driven power transfer to individual machines. Belt drives had a finite limit on their length and operated at right angles to the drive shaft. The buildings which accommodated these power systems were characterized by there distinctive long thin shape on multiple floors. The first distinctive industrial (factory) building typology had evolved amongst the earliest examples being Cromford Mill at Belper in Derbyshire by Richard Arkwright, 1771. 3 The assembly line. The development of compact individual electrical, fluid- or air-driven ‘engines’ released the production machine from the constraint of being tied to a central power engine. These new machines had relatively unlimited capacity and power. Together, these factors allowed machines to be located to match the assembly sequence needed to produce the final product. The assembly evolved. The buildings which accommodated this new form of mass production were typified by being single storey, comparitively large with clear internal spans to provide the flexibility to reconfiguration of the assembly line to suit changes to the product in a more rapidly evolving marketplace. The industrial building typology evolved into large enclosures, single storey with large internal spans.
2 CLASSIFICATION OF PRODUCTION BUILDING TYPES Factories can be broadly categorised as bespoke or generic.
2.01 Bespoke These include: work in controlled conditions, 14.1–14.3. • High-precision Highly tailored to a unique or very specialised process • Primary manufacturing which double as headquarters or • ‘flagship’ manufacturingsites sites. Design will depend on circumstances, but will tend to approximate to laboratory or office type design conforming to Planning B1 classification. 14-1
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14.1 Typical process flow diagram for light production and assembly such as small electronic components’ manufacture, and similar high-technology processes. ‘Kit sort’ refers to the making up of kits of components for assemblers
a Section through unit
b Part plan 14.2 Section through typical factories for light, high-technology production; multi-storey construction, as new or conversion of existing building: could be flatted units
14.3 Light production and assembly: single storey for small-scale and high-technology assembly. High degree of service freedom in roof zone
c Units staggered in plan to reduce site depth required 14.4 Typical ‘nursery’ for light production and assembly, low technology, may be built speculatively
2.02 Medium industries The greatest need for careful and thoughtful design is in this field. These industries can be subdivided into: – medium small-scale engineering and assembly, clothing • Light factories, paint shops, similar to 14.4. – medium batch production of components for other • General factories, medium-sized printing, 14.5 and 14.6. – medium industries requiring intensive use of buildings • Heavy and services as in mass production, 14.7 and 14.8.
2.03 Heavy industries Industries such as steel-making and shipbuilding require spaces (not necessarily enclosed) designed around the work or the mechanical plant, 14.9. Traditionally, it is difficult to build adaptable structures, 14.10, but modern handling techniques enable ‘loose fit’ buildings to be designed 14.11.
3 ADAPTABILITY 3.01 Design for change An industrial facility is designed to either: standards, where the configuration of the building • ‘institutional’ is geared to the requirements of the financial institutions who
14.5 Process flow diagram for batch production and assembly. Sometimes involves the assembly and shipping out of complete sub-assemblies, more commonly the production and dispatch of batches of discrete components
Industrial facilities
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14.6 Section through typical purpose-built batch production building. The spans, typically 18 12 m and trussed roof construction are selected for cheap and rapid adaptation to a variety of uses. Floor loading 25 kN/m2
14.7 Process flow diagram for mass production and assembly. This applies to high-volume line assembly as in the motor industry, with some components being built into sub-assemblies before final assembly on the main line
14.8 Materials flow for mass production does not have to impose a predominantly linear building form. Group assembly ‘cells’ may feed onto a circulatory route, allowing personnel and services to be grouped into specifically equipped zones
fund the development. These requirements manifest themselves in a very flexible building which can be adapted to other industrial process or distribution uses if the initial occupier vacates the building. Typically, the buildings are regular in shape (optimally around 2:1 to 3:1 ratio of length to width) with internal height related to the floor area (typically, 6 m clear to underside of structural obstructions for floor areas up to 2500 m2 and up to 12 m clear to underside of structural obstructions for floor areas of 10,000 m2 and above). Distribution facilities would normally start at a height of 12 m and rise to 18 m where automated ‘picking’ equipment is intended. It is desirable to have the maximum clear internal spans. The most economic form of frame is the portal which can economically span up to 36 m and can be duplicated to increase the width of the building as required. The most economic primary grid spacing is between 6 and 7.2 m. As proportion of the total floor area, the total of office and welfare accommodation will typically range from 10% in total floor areas of 1000 m2 to 5% in total floor areas of 10 000 m2 and more.
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14.11 c Section, and
14.9 Process flow diagram for typical heavy engineering. The workpiece is the centre to which sub-assemblies are routed. It is likely to be disassembled for shipment
14.10 a Section, and
14.10 b Part plan of traditional type. Heavy-duty gantry cranes move the workpiece to the appropriate machine tools and assembly areas
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Recognising the needs of the occupier who is likely to require smaller floor areas, around 1000 m2, the provision of dock levellers is much reduced in comparison with larger buildings of, say, 10 000 m2, where as many as 6–8 may be desirable. Bespoke industrial facilities are usually required where the process is so unique that it is unable to fit within the simple flexible layout of the ‘institutional’ building, cannot be
14.11 d Part plan of recently developed workshop where large workpieces remain static, being built up on special bases that are likely to be employed for transport and installation. Machine tools and components are brought to the workpiece, air-cushion techniques are widely used
contained in a single building or does not require full enclosure. In these circumstances, the building enclosure effectively becomes part of the process. This will limit the future flexibility of the building, in the extreme, rendering it unusable for anything but its intended use. Bespoke buildings are usually associated with capital intensive processes where the process equipment is relatively immovable – in contrast to the type of process equipment that can be readily accommodated in the ‘institutional’ building. For the designer, a thorough understanding of the process requiring a bespoke solution can offer rich opportunity for expressive functional design. The evolving Technology industries tend to conform well to the ‘institutional’ building model which offers greater flexibility for change in the format and type of process. The extreme example being Biotech or Biopharma production processes which are organised as multiple production cells within a large uniform enclosure, each cell is capable of being stripped out and replaced with a completely different process without disruption to the remaining operating cells. There is a reducing requirement for the bespoke industrial facility, at a practical level and resulting from the means of funding of modern industrial facilities. Adaptability must allow: of process to avoid obsolescence • Change • Change of process and product following change of ownership. Changes will normally only be within the broad groupings of building types given in Section 2.02.
Industrial facilities
1 first stage factory 2 first stage office 3 factory expansion
4 various options for office expansion 5 car park 6 heavy vehicle area
14.12 Small or medium-size factory development, with a free-standing office building. The uneven boundary increases the possibility of conflict when the factory and offices expand simultaneously, and restricts commensurate expansion of car parking
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14.14 Mass production buildings have to accept changes in production technology. This plan shows a conventional line assembly that may be adapted to the form in 14.15
14.15 The factory can change to team assembly due to new product. Note localisation of amenity and wet service areas to identify with teams. Chance of opening courts adjacent to amenity areas, though these may change position as production demands 14.13 A large plant with segregated development zones: factory and associated car and truck parking. When the • The factory expands the truck park becomes the expanded car park
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and a new truck park is constructed adjacent to dispatch The administration block and associated car parking, separated from manufacturing by landscaping The ancillary area, incorporating individual growth provision for each element within the zone boundary.
3.02 Design for extension Apart from alterations within the envelope, there may also be requirements for extension; and the design should anticipate this, 14.12 and 14.13.
4 WORKING METHODS 4.01 Alternative methods The alternative methods of work organisation are:
4.02 Linear assembly In this method, machines are arranged along work-travel routes. At each station, component are added until the work has been completely assembled and finished. Supplies of components and materials are needed at each station; and waste must be removed.
4.03 Team technology This appears to restore to the labour force a feeling of responsibility and achievement. The machines are arranged in groups, and all or a substantial part of the work is assembled within the group. There is a need for storage of materials and components. The main planning requirements are for unrestrictive space and strong floors to enable the machines to be relocated at will, with adaptable overhead services systems. Storage and assembly spaces should be interchangeable.
assembly • Linear Team technology. • While the latter is a more recent introduction, there is no indication that it will completely supplant the former. Consequently, production buildings must be able to accommodate either or even both in different areas, 14.14 and 14.15.
5 MACHINE SIZES The sizes of typical machines for light and medium duty industries are shown in 14.16–14.21. The majority of machine tools do not exceed 7.5 kN/m2 in loading on the floor.
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a Plate drill
b Radial drill
c Adjustable multi-drill 14.16 Drilling machines
a Surface grinder
a General purpose chuck lathe
b Hydraulic copying lathe 14.17 Lathes
b Twist drill grinding machine 14.18 Grinding machines
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6 OUTLINE SPECIFICATION OF A TYPICAL MULTI-STRATEGY FACTORY Scope Type of industries for which appropriate
Buildings of this type are suitable for most manufacturing functions, excluding ‘light’, ‘heavy’ and ‘process’ industries.
Size of project
Total area of production space can vary widely. Average size of all projects is 2500 m2, so most are smaller. This specification is suitable for projects from about 1000 m2 upwards.
Type of project
40% of industrial projects are adaptations and extensions of existing premises. This specification sets out the general requirements of those projects, or parts of projects, free from special restraints.
Criterion
Performance specification
Design notes
Requirements of the process Should be designed for general-purpose use and not around a particular process. General-purpose characteristics should be maintained wherever possible, e.g. in stores and production warehousing as well as in production space itself.
Building positioned on site leaving maximum possible room for extension, preferably in two directions.
Plan shape
Probably not critical except where linear flow processes employed. Rectangular form maximises usable area, facilitates extension.
Rectangular plan form with ratio of long to short sides between 1:1 (minimises internal travel distances where no particular traffic routes are dictated by process) and say, 3:1 (average 2:1).
Physical environment
Process requirements will not usually be critical: workplace environment and energy efficiency are very important.
See under ‘Environmental requirements of labour force’. In general, the production process will not require special dust-free conditions, nor will it create a dusty or especially dirty atmosphere. If there are toxic or corrosive hazards within the general production space, these should be isolated by local compartmentation and extraction equipment. High standards of cleanliness (e.g. very exact avoidance of foreign matter) or hygiene (e.g. avoidance of bacterial contamination) for some high-technology factories.
Structural dimensions
Exact plan dimensions rarely critical, except where flow processes employed. Aim should be to optimise convenience for production layouts provided by open space, e.g. the convenience of stanchions for locating small equipment, switches, etc. balanced against the potential adaptability: freedom for service drops and the location of equipment against the cost of greater spans and the loss of overhead craneage.
Span 18 m; bay spacing 12 m or even 18 m (which would permit production line to be turned at right angles if needed). These are proven dimensions in the USA but are greater than those found in many British factory buildings and (excluding 18 m square bays) are unlikely to increase costs significantly over smaller spans.
Internal clear height probably most critical dimension, for once built can only be modified with difficulty. Height needed for high stacking, overhead equipment, possibly facility to install mezzanines (for works offices, lavatories, control gear, extension of production space, etc.), overhead conveyors, etc. Space for services needed above clear height level.
Internal clear height minimum 6 m. Main vehicle entrance doors (ground level loading) 5 m.
Within economic restraints, design for heaviest likely loads.
Ideally point loads of 36 kN, but 25 kN sufficient for general-purpose use for buildings less than 6 m high to eaves. For very dense storage, typically mini-load automated component stores, 30 kN/m2 distributed loading.
Adaptability
Structural loadings
Single-storey building designed as a large open space. Standardised, mainly dry construction, easily extended or modified. Framework able to carry a variety of alternative roof and wall claddings, services and handling equipment. Those external walls not on or near site boundaries designed for easy demolition.
For intensive manufacture, high stacking, overhead hoists or mezzanine floors a minimum height of 7.5 m is recommended.
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Criterion
Performance specification
Requirements of the process (Continued) Provision for services Facility to take any production service (water, steam, gas, electrical power, etc.) to any point within production area with minimum disturbance to building, and therefore production.
Design notes
Production and building services carried in roof space above level indicated by ‘clear height’, with vertical droppers as required to machine positions. This eliminates overhead craneage, but allows monorail hoists and conveyors. Roof structure designed appropriately. Drainage used to be below floor level, although alternative more costly but flexible arrangements are preferable. A permanent grid of drainage runs beneath the floor (a minimum of, say, one run in the middle of each 18 m span) will minimise disturbance.
Provision for movement of materials and equipment
It should be possible for the production engineer to use the type of material-handling equipment best suited to the product and production methods. Use of fork-lift trucks or similar wheeled materials-handling equipment will be general; overhead conveyors may be used. Cranes more usual in engineering than other industries. Heaviest floor loading is likely to result from wheels of fork-lift trucks (36 kN) and point loads from stacked storage cages and from pallet racking.
Separate foundations will be provided for any special or heavy equipment, especially that which vibrates. Wherever possible, the upper surface of such foundations will be at or below finished floor level. Much equipment is now ‘stuck-down’ to the floor. Conventionally, an RC floor slab with integral granolithic finish is used, although deterioration of the floor finish is a common problem in industrial buildings. Durable floors can be obtained, but they require a suitable base, good workmanship and close supervision. Particular finishes may be needed to resist attack from acids or oils used in certain processes.
Support for production loads
There are two opposed points of view about supports for such production loads as conveyors, local hoists and other overhead equipment. One is that since production loads cannot be predetermined, they should not be allowed to bear on the building structure, and should be loads carried either on the plant or on a separate structure, as and when this becomes necessary. This can lead to substructures inhibiting floor area and future flexibility. Although initially more expensive the preferred alternative is to design the roof structure to carry a general minimum of local loads, and to provide the facility to suspend conveyors, etc. at will.
Design assumptions might be that bottom boom of trusses (assumed spaced at 3–3.6 m centres) carry uniformly distributed load of 8 kN/m run, and a point load of 10 kN on any panel point at, say, 3 m centres. Structural supports for heavier loads are then provided on an ad hoc basis by the production engineer.
Environmental requirements of the labour force Visual environment
Practically all visual tasks will be met by illumination levels within the range of 200–750 lux; illumination in the middle of the range will be most common. Limiting values of glare index (as IES Code) are likely to be within 22–28. Colour schemes should be designed both to assist the distribution of light and to minimise fatigue. Natural light design levels: warehouse, packing, large assembly, heavy forging, casting, saw mills, Daylight Factor 2% (say 10–15% floor area) 300–500 lux: Bench and machine work, fine casting, motor repair, general office work, average general purpose lighting, Daylight Factor 4–5% (say 12–15% floor area) 500 lux: Drawing work, medium assembly, weaving, small typesetting, Daylight Factor 6% (say, 15–20% floor area) 500–750 lux: Small inspection and assembly, small bench and machine work, 1000 luxþDaylight Factor 10%.
Either daylight or ‘windowless’ design. If daylight design, ‘north light’ is a useful compromise between even light level and energy conservation. View windows in external walls. Fluorescent lighting installation arranged in regular pattern over whole production floor to give 300–500 lux consistent illumination level Emin =Emax must be at least 0.7 wired in three phases to reduce flicker, and in trunking for simple replacement. Point luminaires may be used in areas of higher headroom, or to provide a high and even intensity. Reflecting surfaces decorated with colours of high reflectivity (e.g. underside of roofs: Munsell value 9), but care that glare from surfaces does not disturb machine operators, e.g. fork-lift truck drivers. For 10% and over use PSALI (permanent supplementary artificial lighting installation). For a general purpose building and for resale the design level should not be below a Daylight Factor of 5%. The method of achieving this must be checked against insulation regulations.
Industrial facilities
Criterion
Performance specification
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Design notes
Environmental requirements of the labour force (Continued) Thermal Optimum values of temperature, air movement, etc. environment will depend largely upon nature of work – whether, for example, it is sedentary or active. Main environmental problem will be to avoid uncomfortable heat in summer. Minimum temperatures: heavy work 10 , light work 13 C sedentary 16 C.
For most light industry plant should be able to provide air temperature of 18–21 C. Mechanical ventilation, at least in factories of average or greater size. Air-change rate (fresh air supply) minimum 5 l/s/person
Acoustic environment
Production processes highly variable in noise output. Control by encapsulating machinery and by using interspersed storage stacks.
Thermal insulation material can give a measure of acoustic control, particularly in providing absorption.
Fire protection
Some industries are regarded as having ‘abnormal’ fire risk because of the process or materials used; building design will be affected by requirements for additional compartmentation. Generally, fire hazard is classed as ‘moderate’ to ‘low’. The general requirement of fire safety, of a maximum division of the production area into self-contained fire-resisting compartments, is at variance with the general production need for open space, and should be carefully considered. The requirements of the occupiers insurers may be more onerous than the requirements of Building Control. The most common standards to refer to are FM Global and LPCB – Loss Prevention Certification Board.
Fire division walls may be required to obtain acceptable insurance rate. Areas will depend on process, etc. ‘Fire curtains’ in roof space. Fire vents in roof surface of total area not less than 1% of floor area. Avoidance of combustible materials in sheeted claddings. Sprinklers are also being increasingly required by insurance companies, both over the process and in the roof depth to protect services.
Explosion hazard
Not normally considered critical, but can be accommodated with blow-out panels, or placing part of process outside the main building.
Building economics
The cost of using a factory building is an important element in the long-term cost of manufacturing. Nevertheless, without adequate justification, few managements are prepared to pay more than the minimum to obtain their essential specification, one reason being that investment in plant, equipment, perhaps labour is likely to show a higher return than investment in buildings (see Sections 3.01 and 3.02).
A ‘basic’ specification: concrete floor slab; exposed structural framework and services; simple finishes, such as painted steelwork, untreated concrete, fairfaced brickwork; self-finished insulating materials forming roof lining.
14.19 Cold sawing machine
14.20 Gear cutting machine
7 NON-PRODUCTION ACCOMMODATION
offices for the local administrative staff, or the com• Executive pany headquarters where these are not elsewhere. This type of
7.01 Offices There is a tendency for administrative and production space to be interchangeable. Two types of offices will be required in close conjunction with the production space: desk space in sight and proximity of work super• Foreman’s vised. This is formed from easily demountable components to allow for rapid relocation. Sometimes to avoid floor obstructions this accommodation is raised to mezzanine levels where visibility is improved.
accommodation is designed in accordance with Section 16, Offices, Shops and Railway Premises Act 1963, and will depend on the numbers to be accommodated. As a rough guide, allow 10–15% of the production floor area, or 5 m2 per person.
7.02 Lavatories For sanitary accommodation see Chapter 5. A first aid facility is normally provided in conjunction with this.
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the importation of food into the working area may need to be discouraged. Canteens are therefore nearly always now provided. See Chapter 17 for details of design.
14.21 Hydraulic pedal press 7.03 Canteens Staff are not allowed to eat in dirty or dusty surroundings. If the process demands a clean environment the reverse may apply, and
8 BIBLIOGRAPHY Workplace (Health, Safety and Welfare) Regulations 1992 The Regulatory Reform (Fire Safety) Order 2005 Building Regulations 2000 (Consolidated) and The Building (Approved Inspectors etc.) Regulations 2000 (Consolidated) LPCB, Red Book, Volume 1: List of Approved Fire and Security Products and Services, Volume 2: Directory of Listed Companies, Construction Products, and Environmental Profiles & Assessments FM Global Guides, Data Sheets, Equipment Hazards, Fire Prevention and Control, Fire Fighting and Fire Service, Hot Work, Human Factors, Natural hazards, Property Loss Prevention Solutions, Proerty Protection Jit Factory Revolution: A Pictorial Guide to Factory Design of the Future, Hiroyuki Hirano, Productivity Press