Explosion resistance
In various living environments, sectors and business processes, it is important for buildings to provide resistance to a possible explosion. That can be achieved by means of explosion-resistant elements, including doors. It is important that quality is guaranteed for these products. Various standards are available for this. The EU is trying to create uniformity in rules. This is why most countries, including the Netherlands, follow the European standards: EN13123-1, EN13123-2, EN13124-1, EN13124-2.
What exactly is an explosion?
To understand what these standards describe, it is important to know what exactly an explosion is and what its consequences can be. An explosion is the direct result of the rapid discharging of large quantities of energy. An explosion can be subdivided into various phases, shockwaves and velocities. It can manifest itself as different effects, such as a fireball, explosive pressure, ground shock, rebound pressure load, (flying) fragments/debris and impact of penetration.
Units of static load
Various units are available for expressing a static load:
• kN/m² (kilonewton per square metre)
• bar or mbar (millibar)
• psi (pounds per square inch)
• kPa (kilopascal)
• psf (pounds per square foot)
Standards for specifications and classifications
The EN13123-1 & EN13123-2 standards describe all the specifications of the classifications for the explosion resistance of objects such as doors. They describe the criteria that the doors have to meet in order to achieve the classification. The European EN13123-1 standard is aimed at the classifications that apply to a door tested using a shock tube. The European EN13123-2 standard is aimed at the classifications that apply to a door tested in an outdoor situation.
Testing standards
The EN13124-1 & EN13124-2 standards describe conditions and specifications for the performance of explosion resistance tests. They describe how the explosion resistance of elements, including doors, should be tested. The European EN13124-1 standard describes the conditions and specifications for testing explosion resistance using a shock tube. The European EN13124-2 standard describes the conditions and specifications for testing explosion resistance in an outdoor situation.
The classifications and associated conditions for testing using a shock tube:
| Resistance classification | Peak pressure (bar) | Positive impulse I + (bar.ms) | Duration (ms) |
| EPR1 (S/NS) | 0.5 | 3.7 | 20 |
| EPR2 (S/NS) | 1 | 9 | 20 |
| EPR3 (S/NS) | 1.5 | 15 | 20 |
| EPR4 (S/NS) | 2 | 22 | 20 |
The classifications and associated conditions for testing in an outdoor situation:
| Resistance classification | Mass of TNT explosive charge (Kg) | Distance (m) | Reflected pressure (bar) | Reflected impulse (bar.ms) |
| EXR1 (S/NS) | 3 | 5 | 2.5 | 3 |
| EXR2 (S/NS) | 3 | 3 | 8 | 5 |
| EXR3 (S/NS) | 12 | 5.5 | 7 | 7 |
| EXR4 (S/NS) | 12 | 4 | 16 | 10 |
| EXR5 (S/NS) | 20 | 4 | 28 | 15 |