One Person In.
The Door Behind Them Locked.
Door interlock systems enforce controlled, sequential entry — preventing tailgating, piggybacking, and unauthorised access in your most sensitive areas. Installed entirely by our own certified engineers.
What it is
A door interlock (or mantrap) is a controlled entry sequence where the first door must fully close and lock before the second door can be opened. Only one person — verified — passes through at a time.
Best suited for
- ✓ Server rooms & data centres
- ✓ Pharmaceutical clean rooms
- ✓ Bank vaults & safe rooms
- ✓ Research & laboratory entry
- ✓ High-security perimeter gates
The Problem It Solves
Tailgating
The most common physical security bypass — a second person follows an authorised user through an open door before it closes. A door interlock physically prevents this by design, not by policy.
Piggybacking
A second person enters with the knowledge and consent of the authorised user — a contractor, a visitor, a colleague in a restricted zone. Interlock sequences require individual verification for each person.
No Delay = No Control
A single door with an access reader can be held open, propped, or rushed. An interlock provides a physical enforcement mechanism that cannot be bypassed by social engineering.
Scope of Work
Interlock Types
Standard Airlock (2-door)
Entry lobby → reader → first door → enclosed space → reader → second door. One person at a time. Most common in server rooms & clean rooms.
Extended Airlock (3-door)
For environments requiring a full decontamination or change-of-clothing zone between outer and inner access areas. Used in pharmaceutical & biosafety labs.
Vehicle Interlock
Oversized interlock for vehicle entry checkpoints — barrier gates with biometric booth for driver verification. Used in data centres & secure compounds.
Lock Type Comparison
| Lock Type | Fail State | Holding Force | Typical Use |
|---|---|---|---|
| EM Lock | Fail-safe (unlocks on power loss) | 600–1,200 lbs | High‑security doors, mantraps |
| Electric Strike | Fail-secure (locks on power loss) | N/A (mechanical) | Office doors, retrofit |
| Magnetic Shear | Fail-safe | 1,500 lbs | Very high‑security, sliding gates |
Our Process
Real Installations
Our certified engineers at work.
Technician fitting EM lock to door frame – close-up, Mumbai
Engineer wiring door controller panel with sensor cables – Bengaluru
Finished interlock lobby – clean double-door installation, Pune
Client Success Story
Challenge: Frequent tailgating into GMP‑classified clean rooms; audit findings flagged unauthorised personnel entry.
Solution: Installed a 2‑door interlock with biometric readers and integrated CCTV. Each entry requires fingerprint verification; the system logs every transaction with a photo capture.
✓ Outcome: Zero tailgating incidents in 12 months, passed regulatory audit with full audit trail, improved staff accountability.
Frequently Asked Questions
Q1: What is a mantrap and is it the same as a door interlock?▼
Yes. A mantrap is a physical security enclosure with two interlocked doors; 'door interlock' refers to the electronic logic controlling them. Both terms are often used interchangeably.
Q2: What size does the enclosed space between the two doors need to be?▼
For a standard person interlock, the space should be at least 4–6 feet deep and 3–4 feet wide. For wheelchair access or equipment, we design larger spaces during the site survey.
Q3: What happens if someone is trapped between the two doors?▼
We install emergency release buttons inside the interlock, a timer override (e.g., 30 seconds), and a fail‑safe mechanism that unlocks both doors on fire alarm or manual emergency.
Q4: How does the fire alarm override work?▼
The interlock controller receives a dry contact signal from the fire alarm panel. On activation, both doors unlock immediately, allowing free egress.
Q5: Can the interlock integrate with our existing access control system?▼
Yes. We can connect the interlock controller to your existing access control system via Wiegand or OSDP. If you have a mixed environment, we can also install a standalone interlock that works alongside your current readers.
Q6: What is the difference between an EM lock and an electric strike?▼
An EM lock is a magnetic lock mounted on the door frame; it requires power to stay locked (fail‑safe). An electric strike replaces the mechanical latch; it can be fail‑secure (locked on power loss). For mantraps, EM locks are preferred because they fail safe during power failure.
Q7: Can the interlock log who entered and when for each individual door?▼
Yes. The interlock controller logs every access event with timestamps, user ID, and which door was opened. This data is exportable for compliance audits.
Q8: What is the maximum holding force of an EM lock and why does it matter?▼
EM locks range from 600 to 1,200 lbs holding force. For high‑security applications (server rooms, vaults), we use 1,200 lbs locks to prevent forced entry.
Q9: Can we have a camera inside the interlock space?▼
Absolutely. We often install a small dome camera inside the mantrap to visually verify the person and capture any attempts to hold the door open.
Q10: How do we handle a medical emergency where someone collapses inside the interlock?▼
We provide emergency push buttons inside and outside the interlock that bypass the sequence and unlock both doors immediately. This complies with life safety codes.
Q11: How long does installation take for a standard 2-door server room interlock?▼
Typically 3–5 days, including civil prep (door frame reinforcement, conduit), wiring, controller setup, and testing.