Security portals

Security portals are interlocking entry portals: two rated doors in sequence that admit one person at a time. The second door only opens once the first has closed and the occupant is authorised. ArxBridge supplies and installs them for high-security entrances across the UK. They are the entrance-control flagship of the security range.

• Interlocking doorsOne person admitted per cycle
• SR3 and SR4Common rating choices
• Tailgating controlAccess control integration
• LPS 1175Forced entry rated leaves

What security portals are

A portal is a small secure lobby with a door at each end, interlocked so both cannot be open together. A person enters, presents credentials, the first door closes behind them, and only then does the second door release. If authorisation fails, the person is held between the doors or released back outside, depending on the site procedure.

The interlock defeats tailgating: the technique of following an authorised person through a door before it closes. It also gives the access system a controlled space to verify identity, check for duress signals, or hold a person for search. Each leaf is a rated doorset to LPS 1175, commonly SR3 or SR4. The LPS 1175 guide explains the ratings.

A portal is a procedure as well as a product. The interlock logic, the duress handling and the failure modes are agreed with the site security team before manufacture, because they shape the control system.

Which rating do you need for security portals

SR3 suits most commercial high-security entrances; SR4 follows where the threat assessment or the insurer names it. The detection and logic specification matters as much as the leaf rating: a portal that cannot reliably detect two people is a lobby, not a portal.

How portals are built

The portal is a self-contained steel structure: two rated leaves, rated side walls or screens, a ceiling, and a floor able to carry the detection system. Leaves are LPS 1175 doorsets with the interlock hardware integrated, so the locking that enforces the sequence is part of the tested assembly rather than an add-on.

Control is by a dedicated controller running the interlock logic: door position, authorisation, occupancy sensing and duress inputs. Single-person detection uses weight measurement, volumetric sensing or a combination, tuned to the site’s false-alarm tolerance. The whole portal is factory-built and tested as a unit, then installed as one assembly, which keeps the interlock timing precise.

Pairing security portals with other ratings

Ballistic ratings can be engineered into portal leaves and screens where firearms are part of the threat. Blast ratings apply to portals on the facade of buildings facing vehicle-borne attack (see blast resistant doors for the door discipline). Gas-tight doors and blast valves serve a different purpose, protecting against airborne hazards (see attack, blast and gas protection).

On the approach to the building, portals work behind vehicle barriers and rated gates (see sliding vehicle gates). Each combination is engineered as one package; state every rating at quote stage.

Where security portals are used

Banks use portals at staff entrances and cash handling areas to stop tailgating into secure zones (see banking and finance). Data centres place them on the route into data halls, where one unauthorised person is one too many (see data centres). Government buildings, laboratories and high-value commercial sites use them at main staff entrances. The common factor is a site where identity must be certain before entry.

What sets the cost and lead time for security portals

The detection system is the main variable: weight-based single-person detection, volumetric sensing and biometric readers each add engineering and commissioning. The leaf rating sets the steel content; SR4 portals are heavier and need stronger structure. Size matters: wheelchair-compliant portals need a larger footprint than standard.

Integration with the site’s access control and CCTV adds commissioning time, as does agreement of the operating procedure with the security team. Factory build is followed by a works test of the interlock logic before delivery. Installation needs a prepared opening and power and data routes. No prices are published; the quote follows the specification.

How to specify a security portal

1. Name the leaf rating. SR3 (C5) or SR4 (D10) to LPS 1175 for each leaf.
2. Define the detection. Single-person method and the false-alarm tolerance.
3. Set the logic. Authorisation sequence, duress handling and failure modes.
4. Confirm compliance. Escape, accessibility and fire requirements for the position.
5. Send the brief. Opening size, throughput and the site access system for a firm quote.