Fire Alarm Engineer Does Not Mean Smoke Control Engineer

There is a habit in the fire and security industry that probably needs challenging.

A company maintains the fire alarm system, the smoke control system interfaces with the fire alarm, therefore the same engineer gets sent to service both.

On a simple natural ventilation system, that might not immediately cause a problem.

On a mechanical smoke ventilation system, it can become a very different story.

We are no longer talking about nothing more than detectors, interfaces and 24 V control equipment. A mechanical smoke control system can include:

• 230 V and 400 V supplies;
• three-phase extract and supply fans;
• automatic transfer switches;
• variable speed drives;
• contactors and motor protection;
• duty and standby fan arrangements;
• generators and secondary supplies;
• motorised smoke dampers;
• pressure and airflow sensors;
• PLCs and smoke control panels.

At that point, describing the whole thing as a "fire system" does not suddenly make every fire alarm engineer competent to work on it.

Competence Does Not Follow the Cable

There is an odd tendency within the industry to treat competence as though it follows the fire alarm interface.

A smoke control panel receives an input from the fire alarm.

The smoke control panel starts a fan.

Therefore, somehow, the engineer who services the detector is assumed to be competent to test the equipment supplying a 400 V motor.

That does not make much sense.

A competent fire alarm engineer may be perfectly capable of testing the detection interface, confirming the correct output operates and verifying that the smoke control system receives the fire signal.

That does not automatically establish competence to:

• test a three-phase supply;
• fault-find a VSD;
• inspect an ATS;
• measure phase voltages;
• work inside an MCC;
• assess motor current imbalance;
• determine whether an extract fan is actually achieving its design duty.

These are different tasks requiring different knowledge and experience.

The Electricity at Work Regulations do not contain an exemption for equipment because it happens to form part of a fire safety system.

"The Fan Ran" Is Not a Complete Service

One of the biggest problems is how easily smoke control servicing can become a functional tick-box exercise.

Activate the fire alarm.

Damper opens.

Fan starts.

Pass.

That proves something, but not necessarily very much.

If a mechanical smoke control system relies on a secondary electrical supply, was that supply tested?

Was the normal supply actually removed or simulated as failed?

Did the ATS transfer?

Was the secondary supply present and electrically healthy?

Were all three phases present?

Was the phase sequence correct?

Did the fan continue running correctly after transfer?

Did the VSD recover correctly?

Did the system transfer back to the normal supply correctly?

If none of that was tested, then what exactly does "ATS tested" mean?

Operating a bypass or test switch and hearing a contactor change state is useful, but it is not the same as checking the condition of the electrical system.

Some Tests Need the System Energised

This is where the competence issue becomes difficult to avoid.

There are plenty of smoke control checks that can be carried out safely without opening live electrical equipment.

There are also checks that cannot realistically be completed with everything isolated.

For example:

• measuring operating voltages;
• comparing phase voltages;
• checking phase sequence;
• measuring running current;
• comparing phase currents;
• checking the secondary side of an ATS;
• investigating a VSD problem;
• thermal inspection under load.

You cannot meaningfully inspect a connection for abnormal heating when there is no current flowing through it.

You cannot verify the voltage supplied by an ATS while the relevant supply is isolated.

Electrical testing and fault finding sometimes require equipment to remain energised. That does not mean live work should be treated casually. It means the person carrying out the work needs the competence, equipment and safe working practices required for that task.

Calling someone a fire alarm engineer does not provide that competence by itself.

Thermal Imaging Is More Than a Nice Photograph

Thermal imaging is a good example of something that can add real value to smoke control maintenance.

Consider an ATS supplying a smoke extract fan.

It might transfer perfectly during a test.

The fan might run.

There might be no fault indication.

At the same time, one termination could have developed a high-resistance connection.

Under load, that connection may be running considerably hotter than the equivalent connections on the other phases.

A quick thermal inspection while the plant is operating can flag that difference immediately.

The same applies to:

• contactors;
• MCCBs;
• isolators;
• VSD terminals;
• busbar connections;
• motor terminations.

Thermography is not a replacement for electrical testing, and a hot connection does not tell you the exact cause of the problem.

It does, however, provide useful condition information that a basic functional test will never reveal.

A Fan Can Run and Still Fail

Electrical operation is only one part of the problem.

A fan can start normally, rotate in the correct direction and show no fault at the control panel while still failing to produce the airflow required by the smoke control design.

A damper can move without reaching its correct position.

A duty fan can work while the automatic standby arrangement does not.

A smoke shaft can have been altered since commissioning.

A replacement fan can be running at the wrong speed.

A VSD parameter can have been changed.

None of those faults are necessarily found by activating a detector and confirming that something makes a noise on the roof.

Mechanical smoke ventilation has to be assessed as a system.

This Does Not Mean Every Engineer Needs Every Qualification

The answer is not that every smoke control engineer must also be a fully qualified electrician, mechanical engineer, fire alarm engineer and ventilation designer.

That would be unrealistic.

The answer is to recognise the competence boundaries.

One engineer might be competent to test the fire alarm interface and cause and effect.

Another may be competent to inspect and electrically test the fan supplies, ATS and motor controls.

Another may be responsible for airflow and pressure testing.

On some systems, one suitably experienced person may cover several of those areas.

The important part is that companies know where those boundaries are.

A job title is not a competence assessment.

Scope Matters

There is nothing inherently wrong with sending a fire alarm engineer to carry out a limited functional test of the smoke control interface.

The problem comes when that limited test is presented as though the complete mechanical smoke ventilation system has been serviced.

If the engineer has tested:

• fire alarm initiation;
• smoke control panel response;
• damper operation;
• fan operation;

but has not tested:

• the secondary electrical supply;
• the automatic transfer arrangement;
• electrical condition;
• airflow performance;
• duty and standby operation;

then the service record should make that clear.

"Not tested" is useful information.

Pretending that something has been comprehensively serviced when significant parts of it were never assessed is not.

Smoke Control Is Its Own Discipline

The fire and security industry has become increasingly broad.

Fire alarm contractors now routinely encounter smoke control, access control, sprinklers, emergency lighting, building controls and other systems.

Interfaces between systems are normal.

That does not make the systems interchangeable.

Mechanical smoke ventilation involves fire safety, electrical engineering, mechanical plant and control systems.

It deserves to be treated accordingly.

The objective of smoke control maintenance is not simply to obtain a signature on a service sheet.

It is to establish whether the system can reasonably be expected to work when somebody actually needs it.

If the servicing regime cannot answer that question, the industry needs to ask whether it is really servicing the system at all.