黑洞社区

INTRODUCTION

Security is an important consideration for any business, to protect both people and assets from outside threats and promote safe internal operations.

A turnstile or entrance control system is designed to deter or completely stop unauthorised entrants, while enforcing the use of an access control system to ensure the 鈥渙ne token, one person鈥� rule applies. Security levels vary depending on the style and type of product chosen.

Automatic pedestrian access systems are an effective method of managing bi-directional pedestrian access to restricted areas, without creating a fortress-like atmosphere. They are designed to offer a high level of security, while achieving maximum throughput with minimum disruption to people passing through the system. Automatic systems are not a substitute for the physical presence of a security guard or receptionist, but allow them to manage multiple entrances.

This CPD will discuss the components of security entrance lane systems and their installation.

SYSTEM COMPONENTS

Security entrance lanes typically consist of two opposing units, referred to as 鈥渕aster鈥� and 鈥渟lave鈥�. Each of the units is equipped with sensors, a control system and a motor drive system that operates the door wings, opening and closing them as required. In their standard position, the door wings are in a closed position. When open, the standard width of a security lane is 500-660mm 鈥� this dimension is critical to preventing unauthorised access because it ensures that two users cannot enter side by side. Single-wing lanes with just one door wing are also available for narrow entrances or where installation space is limited. Wheelchair accessible lanes are also available with a width of 900-940mm, with much larger door wings.

For additional security, some lanes can be fitted with full-height door wings. This helps to prevent users climbing over, and sensors across the tops of the housing units sound an alert when any breach is attempted.

A side pass gate may be provided as an alternative, supervised means of access for visitors, couriers and those with large pieces of luggage.

Security entrance lanes come in a variety of finishes and designs. Most commonly specified is a powder-coated steel chassis with stainless steel cabinets, but alternative materials include wood and glass, and a range of colours of powder-coating are available to suit corporate branding or existing colour schemes. The top covers can be finished with a stainless steel or glass construction.

In some products, the door wings contain LEDs to indicate the status of the lane or the direction of traffic flow.

Specified systems must be DDA compliant. This indicates whether a particular product is capable of allowing use by a disabled person. Previously this related to the Disability Discrimination Act 1995. The applicable act (except in Northern Ireland) is now the Equality Act 2010. For further information, refer to BSIA Form 173, An Access Control Guide to Disability Discrimination.

Most security entrance lanes are driven by two direct current (DC) motors 鈥� one each in the master and slave units 鈥� with an integral gearbox to open and close the door wings. In a single-wing security lane, the door is powered by a single-phase worm gear motor. The motor is connected to and monitored by a control system that consists of a frequency inverter and a programmable logic controller (PLC). Electric motors offer the advantages of silent operation and reliability. For safety reasons, the door wing can be stopped by hand, and any blocking of the door wing is detected.

As a rough guide to calculating the number of turnstiles that will be required, the total installation capacity per minute can be estimated by taking 15% of the building population and dividing it by five. This is based upon 15% of the occupants entering or exiting the building within a five-minute period.

CONTROL SYSTEMS

Most turnstiles are fully compatible with the majority of available access control systems, requiring only a two-door controller to manage ingress and egress through the units. Two separate inputs per barrier are required to operate the unit in each direction. In most cases, this will be a normally open, going closed connection. Other inputs may include visitor access and override modes and operation controls. Security entrance lanes are often controlled using an external panel, allowing reception or the security guard to control the flow of traffic.

Outputs will give passage confirmation in each direction for accurate occupancy counting and appropriate use of the chosen security method. Alarm state outputs are provided, either remotely or within the unit, to indicate a security breach or misuse.

Security entrance lanes can incorporate a variety of authorisation and management systems, with many physically integrated within the body of the units, including:

• Card readers (proximity or swipe)
• Key pads
• Biometric systems
• Cameras
• Lift destination control
• Card collection systems
• People counters
• Coin/token collection
• 黑洞社区 management systems
• Fire/intruder detection
• Asset protection
• Metal/explosive detection
• TCP/IP ethernet networks

Card readers will typically be mounted on the top of the units, but it may be possible to mount a second card reader on the inside of the units, depending on the product, finish and authorisation system chosen. This can aid wheelchair users who may not be able to reach the top of the cabinet to present their access card.

Most units provide a fire alarm input to allow emergency egress, either allowing break-out or providing unhindered egress if required. In case of a fire alarm, as standard the door wings should open completely, allowing free passage through the barrier. Once the fire alarm signal is cleared, the security barrier closes and reverts to its standby mode. When the fire alarm is reset, the door wings will slowly turn to their closed position. In case of a fire alarm, all other safety features should be disabled 鈥� the fire alarm position always takes precedence over the locked position.

Newer products are capable of direct connection, control and monitoring over existing ethernet networks, ensuring full compatibility with IP access control, CCTV and building management systems with no need for further connection.

SAFETY AND SECURITY SENSORS

The primary function of an entry barrier is access control. During normal operation, the barrier should never come in contact with the user. However, during misuse or attempts to defeat the security features, contact with the moving parts of the security barrier may occur. To reduce the consequences of any contact, security barriers are typically fitted with a number of safety features.

For example, they are designed to close with a force no greater than 300N, resulting in an impact no worse than a mild pinch.

Security entrance lane units are also fitted with infrared sensors, to monitor people passing the door wings and ensure the safe use of the system, with the emphasis on safety rather than security. For optimal safety, sensors are placed around the moving wings. These can delay the closing sequence, but if the central section is blocked too long the barrier will close. If an obstruction is detected, it will reopen.

For security, the door wings will close to block the passage if any attempt is made to enter the lane from the non-authorised side. When in the closed position, the door wings will always be locked, preventing unauthorised movement by hand.

Systems are designed to prevent tailgating. When an authorised user is closely followed by an unauthorised user, the authorised user is allowed to pass through and the barrier will then attempt to close in front of the second user, preventing passage while sounding an alarm to alert staff of a breach.

INSTALLATION

The integrity and durability of all security turnstiles depends greatly on their fixing. Units must be installed on a structurally sound, level surface to ensure reliable operation. For most buildings, raised access floors are required to provide a void below floor level through which building services can be routed, offering quick and easy access and the ability to replace essential services over the lifetime of the building. Relevant standards on raised access floors include National 黑洞社区 Specification NBS K41 and BS EN 12825.

Therefore, it will typically be necessary to install a sub-floor fixed to the structural slab, to which the turnstiles are then affixed. This means that the installation of turnstiles can be left until the very end of the building programme, allowing free and safe access during the fit-out phase and ensuring that all services and surrounding finishes can be completed. Specialist fixings are also available to allow installation on soft screed finishes.

All units will require a number of input and outputs which are facilitated by conduits located within the floor. Designers should refer to the system manufacturer for details.

In existing locations, where the user does not wish to damage the existing floor, the majority of turnstile types can be mounted on raised plinths which allow the units to be easily removed, and do not necessitate the adaptation of floor finishes. This is an advantage in listed buildings, or where a tenant desires the ability to move turnstiles from one location to another in future to meet changing operational requirements without the need for expensive remedial works. Full-height units can be cabled from above, which makes installation easier because less disruption is required to the floor.

Each security turnstile requires a separate power supply, fire alarm connection and data cables to and from the card readers and the access control system. The required services are generally housed in conduits either run through the floor or through an existing structural slab, although this would require the involvement of a specialist diamond drilling contractor.

It is recommended that a minimum of two preventative maintenance visits are carried out on all turnstiles per year, though in areas of high traffic or abuse additional visits may be appropriate.