Commercial Door Access Control Systems: Biometric or Card Access System Pros and Cons

The access control decision you make today will shape your security for years to come. It's worth getting it right.

Card-based systems and biometric readers each solve different problems. Cards cost less upfront, scale easily, and keep you clear of the data protection complexities that come with storing fingerprints or facial templates. But they can be lost, stolen, or quietly passed to someone who shouldn't have them. Biometric systems eliminate that risk entirely - nobody can lend their fingerprint - though they bring higher costs and stricter compliance obligations.

For most commercial premises, the answer isn't choosing one or the other. It's understanding where each technology makes sense within your building, and how proper monitoring ensures you actually know when something goes wrong.

The Big Picture

Before diving into the details, here's what matters most for effective access control:

• Card systems give you flexibility and simpler compliance. They're cost-effective, easy to manage, and don't trigger the special data protection requirements that biometric storage demands.
• Biometric systems provide certainty about who entered. The credential can't be shared, borrowed, or stolen - which matters enormously for high-security zones.
• Hybrid approaches let you match authentication strength to risk. Use cards for general areas, add biometrics where you need absolute certainty about identity.
• Monitoring architecture determines whether you find out about problems in real time or eight hours later. This often matters more than the reader technology itself.
• Martyn's Law introduces new legal requirements for premises with a capacity of 200 or more people. Access control moves from operational choice to compliance obligation.

Martyn's Law: Why This Matters Now

The Terrorism (Protection of Premises) Act 2025 received Royal Assent on 3 April 2025. You have roughly 24 months before it comes into force, which sounds like plenty of time until you realise how much preparation it requires.

The law creates two tiers of obligation. Standard Duty applies to premises accommodating 200-799 people and requires documented public protection procedures covering evacuation, invacuation, lockdown, and communication. Enhanced Duty kicks in at 800+ capacity and adds requirements to actively reduce vulnerability to terrorist attacks.

Your access control system becomes central to meeting these obligations. Controlled entry points enable rapid lockdown when needed. Audit trails document who was present during an incident. Real-time alerts to your Alarm Receiving Centre support coordinated response when seconds genuinely matter.

The Security Industry Authority will provide regulatory oversight, with powers to investigate non-compliance. When they review your preparedness, they'll want to see documented procedures, commissioning certificates, maintenance records, and evidence of regular testing. These demonstrate you've taken security seriously from the outset - not scrambled to add it when the inspector knocked.

Why Monitoring Architecture Matters More Than You Think

Picture this scenario: a door lock fails at 2am. Nobody notices until staff arrive eight hours later. You're not just dealing with a broken latch - you're managing an uncontrolled gap in your security perimeter that's been open all night.

Insurers will scrutinise this. Investigators will question it. If something goes wrong during those unprotected hours, you'll be held accountable.

This is where effective system design makes the difference. We build access control with robust monitoring architecture so silent failures become immediate alerts. When a door is forced, held open too long, or registers multiple invalid PIN attempts, that information reaches your Alarm Receiving Centre or control room straight away - not when someone finally checks the logs.

Access control systems designed to meet recognised British Standards don't simply record who entered. They actively alert you the moment things go wrong, converting potential security gaps into actionable intelligence.

Card-Based Systems: What They Do Well

Card access translates the monitoring principle into daily operations. Every tap creates a timestamped record. Every rejected credential generates an alert. Every door alarm triggers a response.

When a cardholder attempts entry after hours, your monitoring team knows immediately. When someone forces a door, the alert reaches them in seconds. This means faster incident response and better evidence capture when it matters most.

Scalability That Grows With You

Card systems excel at adapting to changing needs. We can add new doors, issue temporary contractor credentials, or revoke access centrally without touching hardware at every entry point. You get control that grows with your organisation rather than constraining it.

Integration with CCTV links footage directly to access events, supporting investigations and insurance claims with evidence that holds up to scrutiny.

Resilience When Things Go Wrong

Battery backup maintains door control during power cuts. Dual-path signalling keeps your monitoring connection alive even when primary networks fail. For sites requiring continuous coverage, this resilience isn't optional - because security vulnerabilities don't wait for convenient business hours.

Biometric Systems: The Trade-Offs You Need to Understand

Biometric readers promise something cards can't deliver: certainty about who actually used the credential. A fingerprint can't be borrowed. A face can't be lent to a colleague. For areas where you need absolute confidence about identity, this matters enormously.

But the technology brings complications worth understanding before you commit.

Accuracy depends heavily on sensor quality and environmental conditions. Dirt on readers, poor lighting, extreme temperatures, and the quality of stored reference templates all affect performance. A poorly specified system generates frustrating false rejections during busy shift changes and locks out legitimate staff when conditions aren't ideal.

When specifying biometric readers, ask your installer about the device's declared False Acceptance Rate and False Rejection Rate, environmental suitability ratings, and how failed-match events are logged for review. These details matter more than marketing claims about convenience.

Data Protection Obligations

Biometric data falls into the special category under UK GDPR - the same classification as health records and political opinions. This triggers obligations that card systems simply don't have.

You'll need a Data Protection Impact Assessment before deployment, along with clear signage at every reader explaining what you're collecting and why. Your system needs role-based access controls limiting who can view or export enrolment templates, because insider threats are real. You'll also need defined retention schedules and secure deletion protocols when people leave your organisation.

Miss any of these requirements, and you're exposed to regulatory action that can make security breaches look manageable by comparison.

How Monitoring and Escalation Actually Work

When a door is forced, or an invalid credential is presented, that event needs to travel through a documented chain: from the field device through your control panel, along a transmission path to an Alarm Receiving Centre desk, where a trained operator interprets it and acts according to your specifications.

Your event alerts depend on threshold settings. Three failed swipes might trigger a desk alert for investigation. Forced-door signals or duress codes warrant immediate escalation - potentially to emergency services depending on your response protocols.

Operators follow established processing protocols, consulting your escalation tree, keyholder hierarchy, and site-specific instructions. Responses match your actual risk priorities, not generic templates.

Bi-directional communication ensures silent failures don't leave you blind. Regular health checks between the operator and panel, conducted at defined intervals, catch developing problems before they become incidents.

We work with you to map these alert priorities and handoff procedures before commissioning, ensuring your monitoring architecture matches your risk profile rather than forcing you into off-the-shelf solutions.

Choosing the Right Technology for Each Zone

The choice between cards and biometrics shouldn't be all-or-nothing. Most premises benefit from matching authentication strength to what's actually at risk in each area.

Cards work well for general office access, visitor management, and areas where credential sharing poses minimal risk. They're cost-effective, user-friendly, and avoid the data protection complexity of biometrics.

Biometric authentication makes sense for server rooms, chemical stores, data centres, and anywhere you need certainty that the authorised person - not just their card - actually entered. The higher cost and compliance overhead are justified when the stakes are high enough.

Hybrid approaches give you both. Card-plus-fingerprint dual-factor authentication verifies what someone holds and who they are. This is particularly relevant where your risk assessment justifies higher assurance levels.

When incidents occur, biometric logs tie individuals to events with certainty. Card logs only confirm a credential was present - not whether the authorised holder actually used it. This distinction matters when investigations happen.

Getting the Installation Right

A compliant installation starts with the installer's certification, not the equipment brand. NSI or SSAIB accreditation confirms the company has been independently audited, maintains calibrated test equipment, employs properly trained technicians, and operates under quality-management oversight that catches problems before they reach your site.

Your access control system should be designed and installed in accordance with relevant British Standards - including BS EN 60839-11-1 for access control equipment, which establishes requirements for system design, event logging, and integration capabilities. These standards ensure your installation meets recognised best practice rather than improvised configurations that might underperform when tested by real incidents.

Documentation That Protects You

We provide commissioning certificates declaring conformity to the relevant standards, logs of door-hardware integration testing, and proof that event thresholds have been verified under real-world conditions. These documents support insurer requirements and provide an audit trail when incidents arise and questions get asked.

They're also increasingly important for Martyn's Law compliance. The SIA may request documentation showing your access control procedures and vulnerability reduction measures. Commissioning certificates and testing logs demonstrate you've implemented appropriate security measures - not just claimed you have them.

Maintenance: Your Insurance Against Silent Failure

A maintenance contract ensures logs remain intact, access rights stay current, and authentication devices function reliably when you need them. Defined response times, annual inspections, and remote health checks keep your system performing as designed.

Without proper maintenance, you risk silent failures that leave you exposed and incomplete evidence when incidents occur and your duty of care gets scrutinised. This isn't a nice-to-have - it's the difference between systems that actually protect and systems that create false confidence whilst vulnerabilities quietly develop.

Before You Go

You now have the framework to choose confidently and the questions to ask that reveal whether you're getting genuine expertise or sales pitches.

Start by mapping your high-risk zones - server rooms, chemical stores, data centres, anywhere the consequences of unauthorised access justify stronger authentication. Consider your Martyn's Law obligations if your premises accommodate 200 or more people, and factor these into your specification from the outset.

When requesting quotes from NSI or SSAIB-certified installers, ensure event-log integration, fire-alarm override, and annual maintenance are included as standard rather than optional extras that get value-engineered away later.

Don't wait to retrofit monitoring architecture when your next security review demands it. Specify the audit trail, reader technology, and ARC integration your operations require today - because bolting on compliance after installation always costs more than getting it right first time.