S 1.10 Safe doors and windows

Initiation responsibility: Building Services Manager

Implementation responsibility: Building Services

If doors and windows represent a transition between safety zones, they must offer sufficient protection. An external door must protect against burglary, for example; furthermore, the accessible windows must be safeguarded. Within buildings, doors forming the border of a fire zone are required to have fire protection quality; furthermore, these doors or the other internal doors may form a second line of anti-burglary protection.

Safety doors and windows are categorised by standards. The protection objective of the area to be safeguarded and the protection need of the institution allows for the selection of the appropriate design of doors and windows:

• The standard DIN EN 1627:2011-09 "Pedestrian doorsets, windows, curtain walling, grilles and shutters - Burglar resistance - Requirements and classification" includes the Resistance Class (RC) categorisation of the constructional elements. Doors categorised as class RC1 to RC4 offer higher protection against break-ins due to their stability (for example, for use in server rooms, rooms with technical infrastructure, and as basement or delivery entrance doors). Usually, resistance classes RC5 and RC6 are only appropriate under very special requirements and correspondingly are of no importance in connection with IT basic protection considerations.

• When designed as self-closing fire-resistant doors, and possibly even as smoke seal doors (such as a fire-resistant door T30 according to DIN 18082 "Fire barriers"), they delay the spreading of a fire.

• When designed as self-closing smoke control doors (DIN 18095-1 "Doors; Smoke control doors; Concepts and requirements"), they prevent smoke from spreading. The smoke from a fire can contain particles that are so fine that they can easily penetrate pressure compensation holes and ventilation openings on hard disks. However, they are still far too large when compared to the operating height of a hard disk read head and can cause enormous damage to the read heads.

A door can also include a combination of several protection features; for example, there are smoke seal fire protection doors that simultaneously offer anti-burglary protection.

The safeguarding measures of all surrounding constructional elements must offer equal protection:

• When using burglar-resistant doors in the façade zone, the use of burglar-resistant windows or façade elements (see DIN EN 1627-1630:2011 "Pedestrian doorsets, windows, curtain walling, grilles and shutters - Burglar resistance") must be considered.
• Furthermore it is inappropriate to install a burglar-resistant door of the highest resistance class in a plasterboard wall.
• When installing a fire-resistant or smoke seal door, it must be ensured that the wall around it is equally fire-resistant and sealed to smoke and that there is no way to bypass the door through an open fanlight or an unsealed cable entry.

Requirements for the design of safety doors can be found in safeguard S 1.47 Separate fire zone and S 1.19 Protection against entering and breaking.

In terms of fire protection, it makes sense to use safety doors in other areas in addition to the areas prescribed by the building inspectors and fire department (see S 1.6 Compliance with fire-protection regulations), particularly in rooms requiring protection such as server rooms and document or data media archives. A balanced protection concept must be developed for rooms with high protection requirements that takes the installation of safety doors and the warning and alarm system into account for the purpose of examination and intervention. If a potential attacker has an entire weekend to try to break in to a building, then not even a high quality burglar-resistant door will not be able to keep him from achieving his goal of stealing or destroying data or equipment.

Regarding equipment of the computer centres, the doors, including their installation situation, should be based on resistance class RC3 as per DIN EN 1627-1630:2011 as minimum value. Only if very favourable conditions are present for safety, in particular if the intervention time of supporting forces is short (maximum: 2 minutes), an RC2 door may be used in exceptional cases. If the intervention time of supporting forces is 5 minutes or higher, then even an RC3 door should be considered to be insufficient so that installation of RC4 doors will be recommended. These considerations apply accordingly to all other constructional elements forming the computer centre shell.

Note: The goal of the break-in could be to manipulate data or IT systems. For this reason, the integrity of all central IT systems should be checked after a break-in (see also S 6.60 Specification of reporting paths for security incidents for more information).

It must be ensured that fire and smoke control doors are also actually closed and not kept open (which is not permitted) using wedges, for example. Alternatively, doors can be equipped with automatic closing mechanisms that activate in case of an alarm.

Furthermore, it must be checked regularly that the safety doors and windows are functioning properly. They must be in a proper mechanical condition, safe opening and closing must be ensured, and monitoring installations such as closing contacts must work properly.

Review questions:

• Are all surrounding safeguarding measures of windows, doors and walls of equal quality and appropriate regarding burglary, fire and smoke?
• Are the safety doors and windows checked regularly to see if they function properly?
• For the computer centre, are the resistance values of doors, windows and other surrounding constructional elements on the one hand, and the intervention times of supporting forces on the other hand harmonised with one another?