Central sterile services department

General Planning Considerations

Sterilisation department in a hospital

The sterilisation department in a hospital is known by many acronyms, e.g.:

CSD Central Sterilisation Department

CPD Central Processing Area

SSD Sterile Service Department

TSSD Theatre Sterile Service Department

TSSU Theatre Sterile Service Unit

CSSD Central Sterile Service Department (the most widely used term in the South African context)

Location and functional relationship

Functional relationships to other departments

See Figure 1. The CSSD should be centrally located with ready access to all related service areas, such as the ICU, in-patient units and emergency unit. The department should also have direct access, either horizontally or vertically, to the operating theatres.

Deliveries and transportation routes

Trolleys are used as mode of transport for both receivables and deliveries. In order to cater for the high volume of trolleys to and from the CSSD receiving and dispatch areas, the entry/exit points should ideally be separated to create a uni-directional traffic flow and also to avoid cross-contamination through the division of the clean and dirty material.

Access for plant and equipment maintenance

Plant and equipment in service areas would need access from outside the CSSD, in order not to compromise the desired level of cleanliness in the unit. In some situations direct access between the plant area and the steriliser is required in order to allow access for maintenance staff to the equipment controls in the CSSD area side.

Figure 1: Departmental relationships (IUSS:GNS Adult Inpatient Services)

Primary function of a CSSD

The primary function of a CSSD is to provide an efficient, economic, continuous and quality supply of sterilised items, when needed, to all patient-care service points in the hospital, and to receive returned contaminated items for cleaning. This process is generally referred to as the “decontamination life cycle” (see Figure 2).

Figure 2: Decontamination life cycle

Activities in a CSSD can functionally be sorted under the following primary zones:

• Dirty Decontamination Zone
• Clean IAP (Inspection and Packing Zone)
• Sterile Clean Zone

In addition to the above primary zones, supporting activities are accommodated in the CSSD.

Support zone

In order to identify the functional relationship between the various spaces, the convention is used throughout this guide to indicate the respective zones in the following colours:

In order to create a work space for maintaining a clean environment suitable for handling sterile articles, access to the red, blue and green zones is restricted and subjected to “red-line” principle.

In addition to the above, the red area (decontamination zone) is divided with a hard barrier from the IAP area, in order to prevent contaminated particles from freely entering the relatively cleaner IAP area. This barrier could be a solid brick wall, or glass wall.

Activities comprising the decontamination cycle should allow a progressive work-flow pattern that commences with a “dirty” entry and receiving area, proceeds to a cleaning, decontamination and drying area, into a sorting and packing area, through to sterilisation and cooling area, to finish with sterile storage, distribution and exit areas.

Figure 3: Work flow through the primary zones

Activities in a CSSD

The main activities of the “decontamination life cycle” taking place in a CSSD can be listed as follows:

• receiving of soiled (and contaminated) returns
• cleaning of trolleys
• sorting returned trays

• sorting, disassembling, cleaning and drying of all returned medical devices
• checking functionality and cleanliness of cleaned medical devices
• assembling, packing and wrapping of trays
• sterilisation
• cooling of sterile packs
• storage of sterilised items
• dispatching of orders
• quality control
• maintenance
• record keeping
• receiving new supplies.

These activities can be classified under the following functional areas:

Decontamination

Decontamination involves the use of automated and manual cleaning to remove harmful blood-borne pathogens on the surfaces of equipment and instruments. Soiled items for re-use (medical devices, textiles and equipment) are received in the sterilising department after use in the various clinical departments. These could be operating theatres, emergency department and various wards. Medical devices, equipment and other contaminated articles will be sorted, disassembled, pre-rinsed and cleaned in the decontamination/dirty area. Used linen is put into linen bags and sent to the laundry. Waste items are sorted into suitable containers, according to policy, for appropriate disposal methods.

If items are heavily soiled a manual washing procedure will precede the automated cleaning process by washer-disinfectors. For manual cleaning, a double- (two-) sink arrangement is optimal, one for cleaning and one for rinsing. Automated washers or washer-disinfectors can be provided as single or double-door designs (the latter to allow for physical separation of the dirty and clean areas of the decontamination area).

Photograph 1: Manual cleaning

Photograph 2: Automated cleaning

Inspection

Decontaminated medical devices and equipment are visually inspected for functionality, damage and cleanliness according to required standards, the manufacturer’s instructions and written protocols.

Photograph 3:

Packing

Decontaminated instruments, equipment and other articles are sorted, assembled, counted and packed prior to sterilizing.

Photograph 4:

Sterilisation

Sterilisation is a defined process used to render a surface or product free from viable organisms, including bacterial spores. Depending on the product this procedure could vary from steam sterilisation, dry heat sterilisation, to low temperature sterilising processes.

Photograph 5:

Storage

Sterile items are stored in a clean controlled environment to prevent re-contamination before use.

Photograph 6:

Figure 4: The decontamination life cycle at a glance

Functional Requirements

Activity zones in a typical CSSD

Figure 5: Dispatch points in the decontamination cycle

Figure 5 above is a variation of the generic ‘decontamination life cycle’, indicating the various dispatch points in the cycle.

Based on this principle, the activity spaces in a CSSD could be organised as per figure 6

Figure 6: Configuration of activity spaces

Decontamination zone

• Receiving and sorting
• Waste disposal 
• Cleaner/sluice
• Trolley wash 
• Manual cleaning 
• Automated cleaning 
• Raw materials and chemicals storage
• PPE area (gowning).

Figure 7: Areas related to the decontamination zone

Inspection and packing zone (IAP Zone)

• Inspection and packing (IAP)
• Sterile pack
• Textile folding
• Raw materials storage
• PPE area (gowning).

Figure 8: Areas related to the inspection and packing zone

Sterile zone

• Sterilisation
• Cooling 
• Sterile pack storage
• Dispatch.

Figure 9: Areas related to the clean zone

Support zone

• Office
• Staff rest room
• Kitchenette
• Female change room
• Male change room
• Manager’s office
• Steriliser plant room.

Figure 10: Areas related to the support zone

Functional relationship between activity spaces

Figure 11: Functional relationship between activity spaces

Workflow

Design solutions should follow work-flow principles, separating dirty and clean areas. The workspaces in the decontamination and clean areas should be designed as open-plan work areas subdivided by benches and/or equipment into functional work areas. These work areas should be arranged to allow for a progressive work flow that commences with a ‘dirty’ entry and receiving area, proceeding to a cleaning, decontamination and drying area, into a sorting and packing area, through to a sterilisation- and cooling area, with sterile storage, distribution and exit areas completing the process. 

It is critical to the functional efficiency and safety of the CSSD that these spaces are sequentially linked for one-way flow-through of instrumentation. The separation between the dirty area, where soiled goods are collected, and the clean area where washed and disinfected instruments are inspected, sorted and packed, is realised by a high throughput pass-through washer disinfector barrier.

Treated instruments are unloaded and managed directly in the clean packing area by different staff.

Figure 12: Work flow through the zones

Material flow

Figure 13: Material flow through the zones

Personnel flow

Figure 14: Personnel flow through the zones

Air flow

Figure 15: Air flow through the zones

Design for infection control

The design of a CSSD plays an essential role in addressing infection control issues to minimise the risk of infection transmission. 

Planning and design features to support infection control should include the following:

• Restricted/controlled access
• Unidirectional work flow, progressing from dirty to clean to sterile areas
• Controlled air flow with positive air pressure from clean to dirty areas
• Containment of steam and moisture, preventing potential contamination of stored sterile articles.
• Building and layout details that would facilitate easy cleaning
• Selection of suitable building materials and finishes
• Selection of fixtures, fittings and equipment with suitable detail, materials and finishes for easy cleaning, and prevention of build-up of harmful organisms
• Adequate facilities for cleaning and waste management
• Access to the area should be limited and controlled. This should prevent any unauthorised person from entering the area without permission
• Staff/visitors should have access to hand-washing facilities, separate from those used for cleaning devices, before entering or leaving the areas.
• The flow of both staff and equipment must allow no cross-over of soiled and clean materials
• The operating procedure for infection control in a CSSD falls outside the scope of this guideline.

Design for Occupational, Health and Safety

Planning and design features to support occupational health and safety include the following:

• Selection of floor finishes with a non-slip finish
• Selection of fixtures, fittings and equipment with suitable detail, materials and finishes to prevent personal injury through accidents or misuse
• Provision of suitable and adequate facilities to support and encourage a high level of personal hygiene, with special reference to hand hygiene
• Provision of adequate dispensing points for the appropriate personal protection items (PPE) for the specific area to enable strict enforcement of PPE requirements in the protection of healthcare workers, especially as preventive measures against HIV aids
• Top-loading, worktop equipment should be accessible to staff members of all heights
• Ill-considered dimensions and layouts of fixtures and fittings could have a significant negative effect on occupational health and safety of staff.

As the requirements of the Occupational Health and Safety Act will apply, this section needs to be read in conjunction with the OHS-related guidelines.

Design for change and technology

Although it is difficult to predict future trends in CSSD technology, it is advisable to allow some flexibility and adaptability in space requirements, electrical consumption and layout, and also in air-handling capacity. Current trends that need to be considered are the following:

• The increasing complexity of surgical procedures requires more intricate equipment and instruments that need specialised care and handling during the sterilisation procedure
• Integrated computerised tracking facilities have become widely used and have become an essential tool in the validation of the sterilisation process
• Changing staff-flow patterns due to changing work-flow patterns as a result of procedural and/or equipment innovations
• Design towards sustainable architecture, i.e. water-saving equipment, and equipment with reduced toxic emissions. Constant improvements and innovations lead to products that run more economically and reach a higher level of environment compatibility 
• The facility should be able to reasonably accommodate access and positioning of possible outsize equipment. Consideration for this possibility should be given from (and including) point of delivery to point of positioning
• It is advisable to allow capacity for extra machinery in the event of increased production demand.

Ergonomic and user-comfort considerations

Sterile services departments should be designed to protect staff from avoidable risks of injury. Badly designed elements such as height, depth and design of workstations and counters, shelving and the layout have an impact on the occupational health and safety of staff. Workspaces should therefore be sufficiently flexible and adaptable to accommodate adequate working space for individual comfort, and to reduce any unnecessary physical stress or risk of injury to the body from any repetitive and/or periodic actions such as lifting, pulling, pushing, etc. 

Ergonomics considers the understanding of human-equipment interaction and design to minimise safety risks and achieve the optimum use of equipment. When particular high risks are identified, these should be minimised when designing the facility – while providing good lighting (preferably natural light), adequate ventilation, plenty of space, and comfortable humidity/temperature conditions. Workbenches and chairs must be height-adjustable, allowing staff to adopt the correct posture when sitting or standing. 

Enough space must be available to allow for organisation of the workspace. All materials, for example those in the packing area, should be located within easy reach of the workbench (packaging materials, indicators, etc.). A similar concept should apply to device-sorting or manual-cleaning areas. There should be adequate space to manoeuvre, queue, and unload trolleys or other means of transportation.  This will allow not only for good ergonomics but also for efficient work practices. 

The provision of a pleasant interior environment can contribute to staff morale. Temperature and humidity control (air-conditioning), in particular in areas where heat-associated equipment (such as steam sterilisers and thermal washer-disinfectors) is used, is preferred. Provision must be made for adequate heat extraction systems from heat generating equipment such as autoclaves and instrument washers. This should be done as close to the source as possible i.e. above autoclave doors and instrument washers. This heat source can be utilized to pre-heat water going to the boilers. Consideration should also be given to ensure there is adequate lighting (preferably natural) and noise control. 

For larger facilities, provision may need to be made for managers’ offices, general staff areas (for eating and drinking) and storage areas that are separated from the decontamination area. Good interior design also contributes to staff morale. The aim should therefore be to create an attractive and cheerful environment throughout the department.

Sound

Noise must be controlled

• A threshold of 60dBA (decibel) must not be exceeded 
• The walls and ceilings should be made of absorbent materials so that they do not reflect sound 
• Insulation of sterilisers and washer-disinfectors in technical walls will reduce the noise level
• Offices should allow confidential discussions to take place in privacy, away from noisy mechanical or high-volume human areas.

Natural light

Natural lighting is highly desirable, especially in the work areas, and should be used wherever possible, especially in areas such as the cleaning and packing areas. However, direct sunlight on work spaces should be avoided.

Natural ventilation

Natural ventilation through opening-section windows should be limited to offices and staff rooms. However, this is not recommended as it could promote contamination of the internal space by outside sources. Mechanical ventilation should be provided through the remainder of the CSSD, with good primary and secondary filters which must be monitored with differential manometers linked to an alarm system.

Communication

Provision must be made for communication systems to minimise the passage of staff to and from the clean zone. Glass partitions, communication panels, IT and video links for data transfer, intercom and telephones can serve as appropriate means of communication. 

Glass partitions should be used to permit observance of the activities within the clean zone (from the outside) without having to enter it. The glass panels must be of a non-opening design and must be waterproof and flush-mounted.

CSSD Area Determination

Determination of size and layout

The size of a CSSD in a hospital is unique to that hospital, as the size, layout and function of a CSSD are defined in the Operational Policy Statement that guides the operational management of the hospital. The operational policies specific to the CSSD precede sketch design stage. These policies are developed by the project team in consultation with health; service stakeholders, who should have the knowledge and experience to analyse the various processes in and related to the CSSD.

These operational policies define the “What, How, When, Where, Who and With What” of any activity and/or process and are major space determinants which could significantly affect the planning and design of the CSSD, as they can have an impact on the size, configuration and the nature of accommodation.  Operational policies will vary from unit to unit depending on a wide range of factors, both external and internal to the CSSD.  

Determining factors external to the CSSD

Examples of these space determinants could include the following:

• number of theatres/case mix
• surgical procedures
• extent of storage in the theatres and wards
• distribution system that will be used (vertical, horizontal, trolleys, lifts)
• amount of space needed for waste management
• processing needs for re-usable textiles (receiving, transporting, collecting, storing)
• staff facilities to be shared with adjacent departments. See annexure A for a generic set of Standard Operating Policies (SOP) for a typical sterile service department.

Determining factors internal to the CSSD

Examples of these space determinants could include the following:

• types of processing equipment to be used (washer, washer-disinfectors, single- or multi-chamber washers, ultrasonic cleaners, endoscope processors)
• types of packaging to be used (disposable wraps and pouches, re-usable wraps, rigid containers
• echnology to be used for sterilisation (high temperature or low temperature sterilisation, other chemical sterilants, steam)
• anticipated inventory storage
• anticipated volume of consumable supplies
• type of documentation and record-keeping system to be used (manual vs computerised)
• instrument inventory
• equipment inventory
• projected workload
• staffing structure – number of offices
• staffing policy - number of staff to be accommodated
• types of cleaning equipment selected such as multi chamber or single chamber
• number of sterilisers and whether front or double sided loading
• emergency sterilisation requirements.

CSSD area determination

Hoët (1989 cited in AFS Working Group, 2008b, p.281) has estimated the following ratios as a broadbased calculation of CSSD space:

• 0.7 m²/bed from 0 to 300 beds
• 0.6 m²/bed from 300 to 600 beds
• 0.5 m²/bed for more than 600 beds.

Based on these ratios, the following table can be compiled:

Table 2:mratio of hospital bed to CSSD area

BED SIZE	CALCULATION	SURFACE AREA
200 BEDS	0.7 m² /bed	210 m²
400 BEDS	0.6 m² /bed	240 m²
600 BEDS	0.5 m² /bed	300 m²
800 BEDS	0.5 m² /bed	400 m²
1000 BEDS	0.5 m² /bed	500 m²
1200 BEDS	0.5 m² /bed	600 m²

AFS Working Group (2008b, p.291) states that the CSSD has few internal corridors, the commonly used net to department functional factor adopted is 1.30. The 1.30 factor anticipates that the internal circulation must be added to connect functional areas and individual rooms. This minimal surface area required can be estimated as being 200m² useful and 260m² net floor areas.  

Based on the above assumption, AFS Working Group (2008b, p.291) calculates the useful surface area using the MSO ratio based on the number of beds used for Medical – Surgery – Obstetrics (MSO), using the following calculation basis:  

Table 3: Ratio of MSO to CSSD area

MSO – NR OF BEDS	USEFUL SURFACE AREA/BED	USEFUL SURFACE AREA	NET SURFACE AREA
< 200 BEDS	200	200 m²	260 m²
200 – 300 BEDS	1,5 m² /bed	300 – 400 m²	400 - 520 m²
300 – 400 BEDS	1,2 m² /bed	350 – 420 m²	450 – 550 m²
450 + BEDS	1,0 m² /bed	450 m²	600 m²

Studies done by Putsep and Cowan (1983, p.8) produced the following ratios depending on the ‘active’ nature of the bed.  

TABLE 4: COMPARATIVE RECOMMENDATIONS FOR ESTIMATING THE SIZE OF A CSSD (PUTSEP AND COWAN, 1983, P. 8)  

NR OF   BEDS	SCANDINAVIA	BELGIUM	NETHERLANDS	RSA1
		m² PER BED
200 BEDS	1,1 m² /bed	0,6 - 1 m² /bed	0,7 m² /bed	1,0 m² /bed23
350 BEDS	1,1 m² /bed	0,6 - 1 m² /bed	0,6 m² /bed	1,0 m² /bed
500 BEDS	1,1 m² /bed	0,6 - 1 m² /bed	0,5 m² /bed	1,0 m² /bed
750 BEDS	1,1 m² /bed	0,6 - 1 m² /bed	0,4 m² /bed	1,0 m² /bed

 

Based on the above data, the areas are as follows:  

NR OF   BEDS	SCANDINAVIA	BELGIUM	NETHERLANDS	RSA3
		TOTAL AREA
200 BEDS	220 m²	160 m²*4	140 m²	200 m²
350 BEDS	385 m²	280 m² *	210 m²	350 m²
500 BEDS	550 m²	400 m² *	250 m²	500 m²
750 BEDS	825 m²	600 m² *	300 m²	750 m²

As the schedules of accommodation on which the above analyses are based have not been included in the study, the equitability of the comparisons is in doubt.  

It is however; clear that the size of a CSSD cannot be generically determined on the basis of statistics or averages. Every CSSD has its own set of area determinants that need to be logically evaluated in order to arrive at an area that is the optimal combination of functionality and cost effectiveness.  

Proportional allocation of space in a CSSD facility

TABLE 5: SPACE ALLOCATION IN A CSSD (PUTSEP AND COWAN, 1983, P.9)  

AREA	NUFFIELD   PROVINCIAL   HOSPITALS TRUST   (1963)	ESTIMATED   AVERAGE –   SWEDISH   PRACTICE	NORWEGIAN   RECOMMENDATIONS   (1978)	HOET   (1981)
RECEIVING   WASHING   DECONTAMINATION	10	19	10	30
CLEAN AREA	35	20	25	30
STERILISATION AREA	5	8	5	25
STERILE SUPPLY
STORE DISPATCH	16	29	25
BULK STORE	11	14	20	15
STAFF AREA   OFFICE   HOUSEKEEPING	23	10	15