Turnstile provide the ability to restrict passage to a single person at a time unlike a  door that, once open, many individuals can pass through.

• Turnstiles and portals manage pedestrian traffic flow and access at checkpoints.
• Turnstile technologies range from a simple, stand-alone rotating tripod with no accounting functions to electrically activated barriers with optical scanners that are components of fully automated access control systems.
• Turnstiles encourage employees and visitors to abide by access control procedures and reduce the need for security personnel to monitor ingress and egress points.
• Some products provide information on the direction of travel and can count the number of pedestrians.
• Often the access approaches are arranged using markings or railings so that people awaiting access will form a line.
• Most manufacturers include audio or visual prompting devices to indicate the direction of travel and alarms for attempts to enter without authorization.

Tumstiles are often found in the main reception area of organisations

Most turnstiles are designed with an area for the card reader to be installed behind the top cover.

When considering the use of turnstiles consideration should be made to the following :

• Customer usability
• installation feasibility
• Operating speeds to ensure no delays
• The number of lanes required
• Fire evacuation procedures
• Height to prevent people jumping the barrier

Type of turnstiles

• speed gate turnstile

•A common type of turnstile is the speed gate which is often seen in reception areas and public transport. The speed gate has several barrier types but a common variety consists of two glass barriers,

• The tripod turnstile

The tripod turnstile has three arms that rotate as passage is granted to an individual. As the arm rotates it drops out of the individuals path. but Tripod turnstiles do not offer the physical barrier

Tripod turnstiles do not offer the physical barrier a speedgate offers as the arm can be crossed by an individual by passing over or under easily.

In a fire activation the tripod turnstiles arm that is at the top, and therefore blocking access, simply drops vertically down. Once the fire alarm is reset the turnstile arm is simply retumed to its position and locks in place.

• The full height turnstile

The full height provides a barrier to individuals that makes bypassing very difficult.

In a fire activation the turnstiles locking mechanism will release thereby allowing free access to any individuals. A gate maybe provided next to a full height turnstile that will also open and allow for a greater flow of individuals who could be held up by the turnstiles

Operation

Turnstiles operate in many different ways. In each application, they limit access using various barriers that revolve, rotate, retract, or lever, Many include provisions for additional access control devices including smartcard, proximity, and biometric devices. While full-height turnstiles may be used in high-security settings, waist high turnstiles are the most common

In turnstile , a pedestrian approaches and walks through or, may swipe a card, wave an access card by a reader, or enter an access PIN on a keypad before walking through. The access control system compares the data entered with the enrollment database and, if entry is authorized, signals the portal to open or the turnstile to release and allow access.

Applications

Turnstiles are used for pedestrian control in airports, schools, stadiums, arenas, perimeter and interior security, retail crowd control, transit fare collection, and lobby or building access control where high throughput is necessary.

Performance Metrics

• There is no single performance standard for turnstiles
• Most are equipped with safety features that allow mass egress in emergencies.
• Several manufacturers have equipment complying with the Americans with Disabilities Act (ADA) of 1990.
• The specific application of access control technology also influences the performance of equipment.
• Turnstiles have relatively high throughput, even though people must pass through the opening in a one-by-one sequence rather than as a crowd. Portals have lower throughput than turnstiles, because the device must open and shut for each person passing through