At 66 storeys, the Marina Bay Suites condominium, where a fire on Monday killed two security guards, is among Singapore's tallest residential buildings.

As private and public housing blocks grow taller, fire safety rules have also kept pace. Residential buildings with more than 40 storeys - also dubbed a super high-rise building - now have refuge floors and fire lifts.

But what exactly are they, and how do they help residents evacuating from a fire?

Here are some frequently asked questions, with answers from the Singapore Civil Defence Force (SCDF).

1. What should I do if a fire breaks out at a super high-rise building?

If you are able to do so, extinguish the fire. Alert others of the fire and dial 995 for the SCDF. Activate the nearest fire alarm. Then, instead of heading down to the first floor of the building, head to a refuge floor. Don't use the lifts. Use the stairs instead.

2. What is a refuge floor?

Refuge floors are special floors that serve as a safe holding area so residents do not have to walk many floors down to the ground level during a fire.

There must be a refuge floor for every 20 storeys in a super high-rise residential building. At least 50 per cent of the gross floor area of a refuge floor must be designated as a holding area for occupants of the building to assemble during a fire.

It is easy to recognise a refuge floor since many developers have turned them into sky-gardens and fitness parks.

A sign, "Fire Emergency Holding Area", has to be displayed inside the staircase and on the wall immediately outside the staircase at the refuge floor.

Marina Bay Suites has three refuge floors, on the 6th, 27th and 46th storeys.

3. Will I truly be safe on the refuge floor?

A refuge floor is generally a safe place to wait during an evacuation. They are naturally ventilated and are made of fire-resistant materials.

No commercial activities or residential units are allowed on the floor although it can be used as an exercise area, provided the equipment there is non-combustible.

Refuge floors are linked to all blocks of a super high-rise residential building and so are easily accessible to all residents. They also serve as escape routes for those evacuating from a block where the fire is to other blocks that are not affected.

SCDF fire-fighters can mount search, rescue and fire-fighting operations from these refuge floors.

4. What if I live in a really tall HDB or building that does not have a refuge floor?

Other tall HDB blocks - some as high as 40 storeys - may not have refuge floors. But they still have extra fire-safety features. These include an emergency power supply for fire lifts and a system of pipes kept permanently full with water, or wet risers. Firefighters can connect their hoses to these wet-risers - which are compulsory for buildings above 60m - on higher floors

5. What is a fire lift?

A fire lift is a special elevator housed in a protected enclosure and equipped with an emergency power supply.

When a fire alarm is activated, a fire lift is programmed to head back to the ground floor. It will automatically be grounded and will remain stationary at the ground floor.

The lifts can then be operated by SCDF fire fighters via the fireman switch.

Fire fighters use the fire lift to support fire fighting operations and to evacuate occupants, especially those with disabilities.

All high-rise buildings above eight storeys are required to have one fire lift. Super high-rise residential buildings should have at least two fire lifts.

6. Should I use a fire lift to escape the building then?

This is not advisable. In a fire, lifts should be avoided. You should evacuate using the stairs.

Source: SCDF