Structural Conditions

Spatial design of the operating theatre area

What requirements are placed on the interior design

Traditional structural requirements for operating theatre departments are usually based on fundamental hygiene considerations and the associated expediency and include, for example1
    • separation from the rest of the clinic or practice
    • spatial organisation within the department
    • organisation and layout of the rooms
    • easy-to-clean horizontal surfaces
    • etc.
    The specifications in the guidelines with regard to this aspect are limited. One reason for this could be that the infection-preventing effect of structural requirements could not be proven by comparative studies. Only the KRINKO guideline goes into detail on specifications for spatial design.1
The aspect of ventilation is also taken into account in this context.


GuidelineRecommendationCategory (if mentioned)
CDC2“Maintain positive-pressure ventilation in the operating room with respect to the corridors and adjacent areas.”Category IB
“Maintain a minimum of 15 air changes per hour, of which at least 3 should be fresh air.”Category IB
“Filter all air, recirculated and fresh, through the appropriate filters per the American Institute of Architects’ recommendations.”Category IB
“Introduce all air at the ceiling, and exhaust near the floor.”Category IB
“Do not use UV radiation in the operating room to prevent SSI.”Category IB
”Keep operating room doors closed except as needed for passage of equipment, personnel, and the patient.”Category IB
“Consider performing orthopedic implant operations in operating rooms supplied with ultraclean air.”Category II
“Limit the number of personnel entering the operating room to necessary personnel.”Category II
WHO3“The panel suggests that laminar airflow ventilation systems should not be used to reduce the risk of SSI for patients undergoing total arthroplasty surgery.”

Conditional recommendation, low to very low quality of evidence


Operating room: Operating theatres should be self-contained and have as few but sufficiently dimensioned doors as possible. If floor drains are required, techniques should be used to prevent contamination of the surrounding area.

Category II

Grouping of rooms and areas: Rooms or areas for the following functions can be combined for several operating theatres: Anaesthesia induction, patient preparation, anaesthesia discharge, patient aftercare, hand washing, hand disinfection. Other rooms can also be combined if this is possible in terms of infection prevention and function.

Category II

Instrument preparation: If instrument tables are not prepared in the operating theatre, but in a separate room, the same hygienic conditions (e.g. ventilation conditions) should be ensured there as in the operating theatre.

Category II

Staff changing room (staff airlock): In the staff changing room, the clean and unclean sides should at least be functionally separated. Crossing should be avoided in the routing. The unclean side must have sufficient space/cupboards for storing ward clothing and collecting bins for used area clothing, as well as washbasins, WC facilities and showers if necessary. On the clean side, storage facilities must be provided for the protected storage of the daily requirement of clean area clothing as well as facilities for hand disinfection.

Category II

Patient transfer room/area: In the patient transfer area, patients should preferably be transferred using transfer aids. Sufficient waiting areas for beds must be provided in the immediate vicinity. Additional patient changing rooms must be provided for outpatients undergoing surgery. The recovery room should preferably be located at the transition from the operating theatre department to the rest of the hospital and functional and organisational measures should be taken to prevent the principle of the staff airlock from being broken.

Category II

Material supply/disposal: A room or zone must be provided for the supply of materials where the goods are delivered without transport packaging. Accordingly, a separate disposal room must be provided for disposal. Within the operating department, clean goods (sterile goods, medicines, reprocessed equipment, etc.) must be stored in special rooms or in suitable containers in designated areas. Unclean goods (dirty laundry, waste, etc.) must be stored in the appropriate separate transfer room. Sufficient space must be provided for loaned instruments. An appropriate number of dispensers for hand disinfection and examination gloves must be provided throughout the operating theatre.

Category II

Surfaces: The surfaces of the rooms and operational installations (e.g. doors, shelving systems, lamps) as well as the equipment must be procured or positioned in such a way that soiling is minimised and they can be easily cleaned and disinfected. Surfaces must be intact without flaking (e.g. of paint) or surfaces that are difficult to clean/disinfect. The same applies to the storage of materials and equipment.

Category II

Ventilation: If the operating theatre department is equipped with a ventilation system, this must be regularly maintained to ensure that it meets the technical standard. Triple-filtered air is fed into the operating theatres (and preparation rooms for setting up instrument tables, if applicable). The operating theatres are pressurised in comparison to the adjacent rooms. Equipment with independent ventilation systems (e.g. hypothermia equipment for cardiosurgical operations) must be positioned or designed in such a way that they do not pose a risk of contamination of their own.

Category II

The use of LAF/TAV does not have its own infection prevention effect.

Category II

The separation of "clean" and "unclean" operating theatre departments has no infection-preventing effect of its own.

Category II


Denise Leistenschneider, Senior Clinical Consultant
“Infection prevention goes beyond pure hygiene measures and also includes structural requirements.”

Recommended Instructions

OR: Self-contained operating theatres with few but sufficiently large doors and, if necessary, floor drains with contamination-preventing technology1

Grouping of rooms: Grouping of rooms for anaesthesia induction, patient preparation, anaesthesia discharge, patient aftercare, hand washing and hand disinfection1

Instrument preparation: When preparing instrument tables in a separate room, equip this room with the same hygienic conditions as the operating theatre1

Staff changing room: At least functionally separate clean and unclean sides; routing without crossroads; unclean side with sufficient space for ward clothing, collection containers for used area clothing, washbasin, WC and showers if necessary; clean side with protected storage facilities for daily requirements of clean area clothing and facilities for hand disinfection1

Patient transfer: Patient transfer preferably by means of bed transfer aids; sufficient waiting areas for beds in the vicinity; changing rooms for outpatients; recovery room at the transition from the operating theatre area to the rest of the hospital (thereby counteracting the principle of the personnel airlock)1

Material supply and disposal: Room/zone for delivery of goods without transport packaging; separate disposal room; store clean goods in special rooms/containers in designated areas; store unclean goods in a separate transfer room; sufficient space for loaned instruments; appropriate number of dispensers for hand disinfection and examination gloves distributed as required1

General: All surfaces should be as dirt-free as possible, intact and easy to clean; regularly maintain existing ventilation systems; introduce triple-filtered air into operating theatres (and, if necessary, preparation rooms for setting up instrument tables); operating theatres with positive pressure compared to adjacent rooms; ensure that devices with independent ventilation do not pose a risk of contamination of their own1

Requirements for the storage location of sterile goods 5

  • dry
  • dust-protected/low-dust
  • protected from light
  • protected from damage
  • protected from mechanical influences
  • at room temperature (max. 25 °C)
  • protected from extreme temperature fluctuations
  • separated from non-sterile products
  • clean
  • free from vermin

Relevant aspects for recommending the storage period for sterile medical devices5

Loss of sterility
dependent on external influences and effects during storage, transport and handling

Permissible storage period
determined by the Hygiene Commission after assessing the conditions on site

Specified storage period
is only valid if the storage is appropriate and professional

All content and recommendations listed are to be regarded as extracts from the original literature and do not claim to be exhaustive.

Click here to see full list References
  1. KRINKO (2018) Prävention postoperativer Wundinfektionen. Empfehlungen der Kommission für Krankenhaushygiene und Infektionsprävention (KRINKO) beim Robert Koch-Institut. Bundesgesundheitsbl 61: 448–473.
  2. CDC (1999) Guideline for Prevention of Surgical Site Infection. Infect Control Hosp Epidemiol. 20(4): 247–278.
  3. WHO (2018) Global guidelines for the prevention of surgical site infection. World Health Organization 2018.
  4. NICE (2020) Surgical site infections: prevention and treatment. NICE guidelines. Published: 11 April 2019. Last updated:19 August 2020.
  5. DGSV. Empfehlung zur Lagerdauer für sterile Medizinprodukte. Accessed 13.03.2024.

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