What does each part of BS 476 tell you? Why you need to know before choosing building materials for your project



What do the various parts of BS 476 tell us?

Why you need to know before choosing building materials for your tower

Many people choose materials based on aesthetics, price, or acoustic ratings

But there is another equally important matter... "How do those materials behave when a fire breaks out?"

• BS 476 Part 4

Are the materials "non-combustible" or not?

This standard tests whether the material itself can burn. The material is placed in a high-temperature test furnace at approximately 750°C.

If the material does not ignite and does not increase the furnace temperature beyond the specified threshold, it is considered to have passed the non-combustibility test, meaning it is "non-combustible."

Why is this important?

If the material itself is combustible, when a fire occurs, it immediately adds fuel to the fire, causing it to burn more intensely.

• BS 476 Part 6

How much do materials contribute to fire spread?

Some materialsmay not ignite easily, but when exposed to fire,they can release a large amount of heat energy.

This heat is the fuel that allows the fire to expand more rapidly.

BS 476 Part 6 therefore tests how much that material contributes to fire propagation

The test results are reported as the Fire Propagation Index (I). The lower the value, the better.

This means the material releases less heat and contributes less to the spread of fire.

What happens if it fails?

The material may

• Increase fire severity
• Cause room temperature to rise rapidly
• Reduce evacuation time
• Increase structural damage

• BS 476 Part 7

How fast does fire spread across the surface of the material?

Suppose a fire starts on a wall. The question is: how fast will the flames travel across the wall?

Part 7 therefore tests Surface Spread of Flame orthe spread of flames across material surfaces

Results are classified into

• Class 1 ⭐⭐⭐⭐⭐ Best
• Class 2
• Class 3
• Class 4 Worst

Materials achieving Class 1

mean that flame spread across the material surface is minimal under test conditions. If a material spreads fire quickly,the fire will travel rapidly along walls and ceilings,increasing the likelihood that

• Escape routes are blocked
• Damage becomes widespread
• Fire control becomes more difficult

• BS 476 Part 20

Wall systems: "How long can they resist fire?"

Many people misunderstand that non-combustible material = fire-resistant wall. In reality, this is not the case,because even if individual materials are non-combustible,when assembled into an actual wall,there may be

• Open joints
• Structural deformation
• Heat penetration
• Wall collapse

All of these can happen

Hence the standard BS 476 Part 20

This standard specifies the principles and methods for testing the fire resistance of building elements by simulating standard fire conditions using a furnace and a Standard Time-Temperature Curve to evaluate how long building elements can maintain their performance.

What Part 20 evaluates

Wall systems are evaluated based on 3 key aspects

Integrity (E)

Whether the wall can stillprevent flames and hot smoke from penetratingor not. If cracks develop allowing fire to pass through,it is considered a failure.

Insulation (I)

Whether the opposite side of the wallbecomes too hot. If heat penetrates enough to ignite materials on the opposite side,it is considered a failure.

Stability (R)

For load-bearing elements, it evaluates whether they can still support loads without collapsing (this criterion applies primarily to load-bearing elements).

Test results

are expressed as 30 / 60 / 90 / 120 / 180 minutes. The longer the time, the more it enhances evacuation time and fire control efforts.

• BS 476 Part 22

Testing "actual room partition walls"

Part 22 takes the principles of Part 20 and applies them tonon-loadbearing walls,such as

• Room partition walls
• Office walls
• Hotel walls
• Hospital walls
• Conference room walls
• Corridor walls
• Drywall systems

as well as certain types of doors, glass walls, and non-loadbearing ceilings within the scope of the standard

Why the entire system must be tested

Becauseeven if

• The gypsum board is good
• The insulation is good
• The steel framing is good

but if they are assembled poorly, the wall systemmay fail sooner than expected. Therefore,this standard tests the "actual system" as installed in the buildingrather than testing individual materials separately

What about Trandar?

The Trandar Hitech Wall acoustic wall system is not only designed for "sound insulation", but also prioritizes fire safety.

✅ BS 476 Part 6 : Fire Propagation

✅ BS 476 Part 7 : Surface Spread of Flame

✅ BS 476 Part 20 & Part 22 : Fire Resistance testing of Non-loadbearing Wall Systems, evaluating the ability to block flames and heat,

and maintaining wall integrity under standard fire conditions for over 220 - 240 minutes

When used in combination with

Trandar dBphon which has passed ✅ BS 476 Part 4, it ensures the wall system delivers both

• Superior acoustic performance
• Non-combustible materials
• Fire propagation control
• Fire-blocking capability according to wall system test results

Making it the ideal solution for both acoustic insulation and fire safety for high-standard buildings.