When putting precautions against intrusion in place in multi-story buildings, in addition to access doors, particular attention should be paid to windows in the basement and on the ground-level floor. However, the police consider that windows on higher floors are also vulnerable in the case of high-risk collections (they define easily accessible to be up to a height of around 6 m above the ground). When assessing risk, anything that could assist climbing (lightning rods, downpipes, climbing plants or the like) should be taken into account. The wide window ledges, projections and friezes typical of historic buildings could also aid climbing. The height that falls within the "easily accessible" range must therefore be determined for each building on the basis of the risk posed to the collection and the building envelope. It is particularly important to keep the risk of intrusion under constant review - especially prior to any building work (scaffolding!).

Museums, libraries and archives often form part of a row of period houses. The structure and the height of the buildings are similar (number of stories etc.). A risk assessment must be carried out for all potential crossing points between the buildings.

Exterior monitoring refers to monitoring all vulnerable building apertures (doors, windows, smoke ventilation areas, rooflights, air conditioning vents etc.). Various detectors are used to monitor the status of these building apertures, e.g. open (unauthorized opening of a door or window), closed (securely closed), and breakage (intruder attempting to gain entry).

Although intruder alarm systems do not prevent break-ins, they do signal attempted forcible entry at an early juncture so that the crime (the theft of valuable items in a collection for example) could beis thwarted and the perpetrator may even be apprehended. Intruder alarm systems can only perform this function effectively if they are planned and installed appropriately for the particular building concerned and THEN have sufficient mechanical resistance (strong and robust doors and windows, see the relevant sections) to prevent the speedy progress of an intruder.

Room monitoring is used to detect movement in exhibition and storage rooms. It is used in particular to detect perpetrators who have not penetrated the exterior defenses of the building but who, for example, have allowed themselves to be locked in the building after closing time in order to carry out a theft.

Key routes within a building are ones which an intruder or perpetrator who has stayed behind after hours MUST use in order to reach security-relevant areas or cultural artifacts. They may be corridors and stairways, or the foyer, offices or basement rooms. These routes should be monitored by motion detectors in order to trigger an alarm in good time before artworks are reached. Securely locking the interior doors to security-relevant areas is also important here, because these doors are often the last physical barrier before an intruder reaches valuable cultural artifacts.

As well as mechanical protection against being grabbed, valuable artworks to which visitors have direct access should also be electronically secured (object monitoring). Given the usually high number of artworks on display, it is often necessary ? especially for cost reasons ? to select a certain number of exhibits to be protected in this way. This evaluation should take account of criteria such as the nature and weight of the object itself, the material value or cultural significance of the object in question, the form of its presentation, the available options for monitoring by attendants, etc. There are a large number of object protection systems available, see Tips.

VdS Guidelines 3511

Access control systems can be advantageous in particular for larger institutions or ones that have several different user sections. In addition to a master key system - which is a purely mechanical system to control access to high-security areas by means of different key authorizations - an access control system registers and logs data about such accesses. For this the access control system uses electronic keys, cards, transponders, codes (PIN), and increasingly also biometric processes (e.g. fingerprints). This makes it possible to subsequently identify a person and their time of entry. Access control systems can also facilitate access to secure rooms or areas during normal daytime operations (for example enabling faster access by activating a door opener or motorized lock fitted in the door). In contrast to the loss of a key where the whole lock system may then need to be replaced, access control systems can be reprogrammed to change or revoke existing authorizations. Access control systems can also be integrated with an intruder alarm system so that, for example, security zones are armed by the access control system as well.

Video surveillance systems are becoming increasingly important for cultural institutions, although they are no substitute for surveillance by human attendants. As well as the deterrent effect that visible cameras have on visitors, the use of video technology has the following benefits:
- Recording of visitor traffic for subsequent identification of suspicious visitors following an incident.
- Recording of video images in exhibition rooms to subsequently help police reconstruct a crime and identify the perpetrator.
- Verifying alerts received from an intruder alarm or fire detection system.
- Monitoring escape route exits from the building.
- Use of video sensors to augment the intruder alarm system (detecting motion in defined areas, especially outside the building).
According to DIN 33450, the presence of a video surveillance system must be indicated by means of a pictogram. Compliance with data privacy legislation must always be ensured.

If valuable irreplaceable items are presented openly (free-standing or free-hanging), appropriate precautions should be taken to prevent them from being grabbed. First of all, a risk assessment should identify the exhibits for which mechanical protection or object monitoring is essential. Along with the material value or cultural significance of such objects, in particular criteria such as location (near to exits or escape route doors with quick access to the open air), the size and weight of exhibits, or the ease of overseeing/monitoring by attendants or security staff should be taken into account.

This situation requires assessment of the risk that people might gain access to collection rooms from areas used by third parties. The mechanical boundaries and their resistance ratings, electronic security measures and also organizational issues (e.g. shared visitor traffic, escape routes that pass through the other area) should be considered and the risk assessed.

The location of a building to be protected is a not insignificant factor when assessing the risk of break-ins and theft. If they are free-standing without an enclosure, buildings can be approached directly with no restriction, including with transport and getaway vehicles.
This makes it more likely that an intruder will be able to escape quickly - and therefore successfully - with the stolen goods. As preferred easy targets for forcible entry, all exterior doors and exterior windows in the basement and on the ground-level floor must therefore be carefully assessed. Similarly, windows on higher floors must also be assessed carefully if there are features that could assist climbing.

In order to quickly detect any attempted forcible entry, all exterior doors must be fitted with intrusion detectors. They should monitor for open/closed and, depending on the risk factors and building location, also breakage. The open and closed status of doors is monitored using magnetic and bolt contacts respectively. Breakage detectors signal the breakage of the door leaf or any door glazing fitted.
Door glazing:
- An "alarm spider" (an electrically conductive wire loop which is vapor-deposited on a pane of toughened glass; if the glass is broken, the circuit is also broken and an alarm is triggered)
- Alarm wire insert (electrically conductive wires embedded in the glass that trigger an alarm when broken)
- Active glass break detector (sensor affixed permanently to the pane, VdS class C)
- Passive glass break detector (sensor affixed permanently to the pane, only approved in conjunction with intruder alarm systems to VdS class B, as its detection sensitivity and applications are more limited compared with active glass break detectors, e.g. cannot be used on laminated glass)
- Acoustic glass break detector which detects the sound of falling, breaking glass (also only approved to VdS class B)
Door leaf:
An electrically conductive alarm wire mesh woven into a thin layer of fabric is applied to the door leaf or sandwiched between two door leaves. Breaking through the door leaf causes the wire to break and an alarm is sounded.

In order to quickly detect any attempted forcible entry, easily accessible windows of security-relevant rooms must be fitted with intrusion detectors. These monitor for open/closed as well as breakage. The open and closed status of doors is monitored using magnetic and bolt contacts respectively (in exceptional cases the latter can also be replaced by press-open bolts in conjunction with open status monitoring). Breakage detection signals the breakage of the glass pane by means of:
- An "alarm spider" (an electrically conductive wire loop which is vapor-deposited on a pane of toughened glass; if the glass is broken, the circuit is also broken and an alarm is triggered)
- Alarm wire insert (electrically conductive wires embedded in the glass that trigger an alarm when broken)
- Active glass break detector (sensor affixed permanently to the pane, VdS class C)
- Passive glass break detector (sensor affixed permanently to the pane, only approved for intruder alarm systems up to VdS class B)
- Acoustic glass break detector which detects the sound of falling, breaking glass.

As well as exterior doors, easily accessed windows are one of the main targets for forcible entry. Entry can be forced with simple tools (levering up or breaking the glass), which often gives the intruder direct access to valuable collection objects in a short space of time. Windows in basements and on ground-level floors should have higher mechanical stability than those on upper floors. The resistance ratings for windows should be defined and implemented depending on their location in the building, whether they are overlooked or not, the height above ground and how easy they are to access by climbing. Resistance ratings for windows ALWAYS take the whole window element plus its frame and securing in the masonry, the glass and locks used into account. It is usually not possible for existing windows (which may be covered by a conservation order) to reach the defined resistance ratings. In this case it should be investigated whether upgrading with, for example, multipoint or rim locks, additional wall anchors, lockable window handles or break-proof/break-resistant glass is possible. If they are not needed for ventilation purposes, windows can also be mechanically sealed (screwed shut).

The areas to be protected should be kept locked and monitored outside the institution's opening hours.

To make attacks on mortise locks and lock cylinders more difficult, they should be protected by an anti-theft faceplate. This must be high/deep enough so that the faceplate is flush with the lock cylinder. A hardened steel insert protects the mortise lock. The security faceplate is always screwed onto the inside in order not to be exposed to attack from the outside.

To delay an attempted break-in, exterior doors must have a certain degree of mechanical stability, depending on the value of the collections. The door leaf, the hinges, the lock (including faceplate and catches), the frame and its anchoring in the masonry should be assessed.

The intrusion resistance features of a doorset include a suitably thick door leaf along with appropriate matching frames and hinges. Following testing (e.g. according to VdS), the entire doorset including all hardware is assigned a resistance rating. The appropriate resistance rating, e.g. for an exterior door, should be selected on the basis of the risk for the building concerned. The resistance rating of the door is stated on a label on the side of the frame. If the door has no identification label, then it can be assumed that it has no tested resistance rating.

Lock cylinders that are designed to defeat lock-picking - the unlocking of the cylinder by unauthorized individuals (intruders) by means of tools or improperly obtained (copied) keys - must meet certain requirements such as an increased number of pins, for example. For this purpose, cylinders are tested according to VdS, EN and DIN standards and are assigned different resistance ratings. Unfortunately, the three applicable standards (VdS 2156, DIN EN 1303, DIN 18252) use different designations so it is helpful to consult a comparison table or an expert (planner, locksmith).