A protected room can have thick walls and a blast door and still fail if its ventilation leaves an open path for the pressure wave or for contaminated air. Every air intake, exhaust and vent is an opening, and each one needs its own protection. Designing that protection is what turns a strong room into a resilient one.

What resilience means for a building

For a building owner, resilience comes down to three questions: who must be protected, what must keep running, and for how long. A civil shelter protects people for hours or days. A control room in a petrochemical plant must stay manned while operators bring the plant to a safe state. A command post must keep working, sealed from the outside, for as long as its mission lasts. The answers set the protection level, the size of the protected zone and the ventilation it needs.

Industry, defence and civil protection

  • Industry. Refineries, oil fields and offshore platforms, chemical and petrochemical plants and power stations all have rooms that must stay safe during an explosion or a gas release, such as control rooms, substations and muster points. Protected ventilation keeps the people inside able to work and the equipment able to run.
  • Defence. Command posts, communication centres and hardened underground facilities have to operate sealed against blast and nuclear, biological and chemical agents and, where required, electromagnetic pulse (EMP).
  • Civil protection. Civil-defence shelters, emergency hospitals, biosafety laboratories and safe rooms in public and private buildings protect people who cannot leave.

The threats differ, but the principle is the same: a tight envelope, protection on every opening, filtered air supplied at a slight overpressure so that any leak runs outwards, and ventilation that keeps working when the grid fails.

How protected ventilation works

Follow the air from outside to the protected room:

  1. Explosion protection valves sit in each air intake and exhaust and close on the pressure wave from a blast. Andair makes versions with built-in air filters, and valves for sanitary vents and for diesel-generator exhausts.
  2. Gas-tight shut-off valves isolate the system and switch it between normal and protected ventilation.
  3. NBC filtration removes nuclear, biological and chemical agents from the incoming air. Andair’s range runs from a small unit for a single safe room to gas-filter banks for large shelters, and includes mobile filtration units.
  4. Shock-resistant fans and ventilation units keep the air moving. Andair ventilation units can be driven by a hand crank, so ventilation continues if the power fails.
  5. EMP protection for doors, ventilation grilles and diesel generators keeps a facility’s own power and electronics working where the threat includes electromagnetic pulse.
  6. Closures and wall sleeves keep the envelope tight where doors, pipes and cables pass through it.

Swiss-made and tested

Andair has made shelter equipment in Switzerland since 1968. Its components are type-tested and approved by Spiez Laboratory of the Swiss Federal Department of Defence, meet the requirements of Swiss civil defence and are made under ISO 9001:2015. More than 3,000 large protected installations in over 55 countries are equipped with Andair components.

What to decide before you design

  1. The threat and the protection level: blast, NBC, EMP or a combination, and how strong.
  2. The protected zone: which rooms, how many people, and which equipment must keep running.
  3. How long it must stay sealed, which sets the airflow, the filters and the power supply.
  4. Every opening: air intakes, exhausts, sanitary vents and generator exhausts each need their own protection.
  5. Power: grid, generator and manual back-up for the ventilation.
  6. Monitoring: valve positions, filter condition and room pressure shown on the building automation system, so operators know the protection is ready before it is needed.
  7. Testing and maintenance: function tests and filter replacement planned from the start.

Protection is easiest to build in at the design stage, when every opening can be planned. Added later, each opening has to be found, reached and fitted, often in a building that has to keep running.

How Goldmarktech helps

Goldmarktech helps you choose Andair equipment for the protection level your facility needs, coordinates supply from Switzerland, and brings the ventilation’s status and alarms onto your building automation system, so a protected area is watched as closely as the rest of the building. To discuss a facility, talk to one of our engineers or see the Andair equipment we supply.