Smoke-extraction motors can take the heat

Edited by the Engineeringtalk editorial team Mar 12, 2002

Leroy Somer reckons its HT range will set the standard for electric motors designed to withstand the high temperatures experienced during a fire.

Although progress is being made, there are still too many people who die each year as a result of fire, and a major cause of these deaths is smoke inhalation.

Tragic events that we all remember include the Kings Cross underground and more recently, the Mont Blanc tunnel but there are many less well known incidents.

Leroy Somer was the first motor manufacturer in the world to design a unit specifically for smoke extraction in a fire.

The Lucifer was introduced nearly 30 years ago to meet demanding French regulations.

Over the years, different fire safety standards across Europe have resulted in a wide variation in requirements for ventilation systems.

This confused situation will be resolved with the imminent publication of a new European Standard for smoke ventilation systems.

Pr-EN12101-3, covering smoke and heat exhaust systems, has been agreed and is awaiting introduction as a European EN/CE standard.

Leroy Somer reckons its HT range will set the standard for electric motors designed to withstand the high temperatures experienced during a fire.

Different models will operate in ambient temperatures of 200, 250, 300 or 400C for 120min, as required by the latest standard.

The standard allows manufacturers to produce two classes of motor, one restricted to emergency use only (S2) and the other dual-purpose for 'comfort' duty and emergency operation (S1+S2).

Leroy Somer has selected dual-purpose, as its standard.

The HT range of motors has been independently tested and certified by CTICM in France, currently one of only two test houses authorised to carry out these tests.

The certification allows the motors to be used by fan manufacturers and rated for emergency duty in the event of a fire.

The tests as defined in the standard for emergency use only, are made with the motor cold.

For comfort duty, the standard requires that the motor under test has been run to stabilise it.

This is defined as operating at maximum power until its temperature changes by less than 2C in 10min.

Leroy Somer feels that this is too limited, so for total confidence and integrity of the product, it has committed to a series of high-temperature ageing tests.

At the end of these tests, the Leroy Somer engineers were delighted to find that they had designed a motor with a survival rate several times that required by the norm.

Two versions of the HT are available.

The HTA with an aluminium frame covers requirements for 200, 250 and even 300C with outputs from 0.4 to 132kW.

At 300�C, this is a particularly light and cost-effective solution.

The HTC series, currently designed for S2 duty with a cast iron frame, covers requirements up to 400C with outputs from 1.1 to 400kW.

All are rated to IP55, fully sealed against the ingress of liquid or dust and can be used in total confidence in the extreme circumstances of a fire.

They are designed to provide a long operational life within a structured maintenance programme.

The Leroy Somer HT range of motors leads the field in smoke extraction performance for subways, tunnels, industrial and commercial buildings, underground car parks and other similar situations.

It will be a particularly welcome addition to the already extensive range of LS motors for ventilation requirements.