Components and standards

What goes into a shelter, part by part: what each component does, the standard it is built or tested to, how long it lasts and how long it takes to get. Then the standards the rest of the world uses, and how long a build takes.

Who checks what, and how often

Structure

The shell that carries earth, resists blast and keeps water out.

Reinforced concrete shell

Walls 300–600 mm and roof slabs 400–750 mm of reinforced concrete, designed to carry earth cover, the collapse of structures above and blast overpressure.

Standard: IS 456, IS 13920 (ductile detailing), IS 1893 (seismic), IS 4991 (blast)
Life: Designed for 50+ years
Checks: Visual inspection for cracks and damp each year

Earth cover

1 to 3 metres of compacted fill over the roof. The cheapest and most effective radiation shield there is.

Standard: Compaction tested in layers during backfill
Life: Permanent
Checks: Settlement and drainage after each monsoon

Waterproofing system

Low-permeability concrete, external membranes, water-stops at every joint and sealed pipe sleeves. The system is chosen from the groundwater investigation.

Standard: IS 3370 principles for water-retaining concrete
Life: Membranes typically 20+ years
Checks: Sump levels and damp patches after monsoon

Sumps and twin pumps

Collect any water that reaches the structure and pump it out, on shelter power, with a standby pump.

Standard: Sized from site groundwater data
Life: Pumps 5–10 years
Checks: Test run every quarter

Anti-termite treatment

Soil treatment around the structure before backfill.

Standard: IS 6313
Life: Varies by treatment
Checks: Annual inspection

Doors and exits

Every opening is a weak point for blast, radiation and gas, so each one is engineered.

Blast door

A steel door in a steel frame cast into the concrete, rated to the shelter's design overpressure, with gas-tight seals and locking from inside.

Standard: Rated and tested to the shelter's blast class (1 to 3 bar+)
Lead time: 8–16 weeks, made to order
Checks: Seal and hinge service each year

Gas-tight inner door

Creates the airlock with the blast door, so people can enter and decontaminate without breaking the seal.

Standard: Air-tightness tested at commissioning
Lead time: 6–12 weeks
Checks: Seal inspection each year

Escape hatch and shaft

A second way out, placed outside any collapse zone, openable from inside and outside, concealed at the surface.

Standard: Same blast class as the main entry
Lead time: 8–12 weeks
Checks: Opened in every drill

Shielded entry passage

Entries that turn at right angles so there is no straight path for radiation, often with earth cover over the passage.

Standard: Designed into the structure
Life: Permanent
Checks: Kept clear of storage

Air

The system that decides how long a shelter can stay sealed.

NBC ventilation unit

Draws outside air through filters and pushes it into the shelter. Electric, with a hand crank for power failures.

Standard: Units type-tested for shelter use, such as Swiss-approved shelter ventilators
Lead time: 8–16 weeks, often imported
Checks: Run monthly, service each year

HEPA particle filter

Captures fallout dust, smoke, PM2.5 and biological particles. H13 captures at least 99.95% of the most penetrating particle size; H14 at least 99.995%.

Standard: EN 1822 / ISO 29463 filter classes
Life: Replaced on schedule, and after any use in contaminated air
Checks: Pressure drop each year

Gas filter (activated carbon)

Adsorbs chemical agents and many toxic gases. Kept sealed until needed.

Standard: Military and civil protection CBRN filter specifications
Life: Per manufacturer's shelf life; replaced after any exposure
Checks: Seal and date check each year

Blast valves

Fitted on every air intake and exhaust. They close in milliseconds when a pressure wave arrives, then reopen.

Standard: Shock-tested to the shelter's blast class
Lead time: 8–12 weeks
Checks: Movement test each year

Overpressure valves

Hold the shelter slightly above outside pressure so any leak flows outward.

Standard: Verified by pressure test at commissioning
Lead time: 6–10 weeks
Checks: Gauge reading in every drill

CO₂ scrubber and oxygen reserve

For recirculation mode when outside air is unusable, such as during nearby fires. Removes exhaled carbon dioxide; larger classes add oxygen reserve.

Standard: Sized to occupancy and hours of sealed operation
Life: Absorbent replaced by date or after use
Checks: Stock and date check each year

Monitoring

You cannot see radiation or smell carbon monoxide. Instruments do the noticing.

Radiation meters

A survey meter for dose rate inside and outside, plus personal dosimeters. They decide when it is safe to leave.

Standard: Calibrated instruments with certificates
Life: Many years with care
Checks: Calibration as the maker specifies, typically yearly

CO₂, CO and O₂ sensors

Alarm before air quality becomes dangerous. Carbon monoxide alarms are standard in every shelter.

Standard: Certified gas detectors
Life: Sensors typically 5–10 years
Checks: Test every drill, replace by date

Pressure, temperature and humidity

Confirms the overpressure is holding and the cooling is keeping up.

Standard: Read on a single panel
Life: 5–10 years
Checks: Logged in drills

Readiness monitoring

Optional remote alerts for water ingress, battery state and temperature, so faults are fixed long before an emergency.

Standard: Encrypted, minimal data
Life: Per device
Checks: Monthly status report

Power and cooling

In India, cooling is life support, so power is designed around it.

Battery storage

Lithium iron phosphate batteries take over instantly when the grid fails and carry the shelter for 48 hours or more on their own.

Standard: Certified cells and battery management, fire-rated enclosure
Life: Typically 10–15 years
Checks: State of health each quarter

Inverter and charge control

Converts and manages power from batteries, solar and generator, and sheds loads in priority order.

Standard: Certified to Indian electrical standards
Life: 10+ years
Checks: Annual service

Solar array

Concealed panels, or panels stored inside and deployed after an event.

Standard: BIS-certified modules
Life: 25+ years
Checks: Clean and test each year

Diesel generator and fuel

In a vented enclosure, with exhaust well away from the air intake and stabilised fuel.

Standard: Emission-compliant sets; fuel stored to safety rules
Life: Many years with servicing; fuel rotated
Checks: Run under load monthly

Cooling and dehumidification

Inverter cooling sized for full occupancy, with standby units on larger classes, and dehumidifiers to stop mould.

Standard: Sized to about 100 W of body heat per person plus equipment
Life: 10–15 years
Checks: Service before each summer

Water and sanitation

Stored water

Food-grade tanks inside the protected envelope, at least 4 litres per person per day plus reserve.

Standard: Food-grade materials; water to IS 10500
Life: Tanks 15+ years
Checks: Water rotated every 6–12 months

Purification

RO and UV purification, plus gravity filters that need no power.

Standard: Output tested against IS 10500
Life: Cartridges by schedule
Checks: Cartridge change each year

Protected borewell

For Estate and remote shelters, a well head inside or beside the protected envelope.

Standard: Subject to local groundwater rules
Life: Long term
Checks: Water quality test each year

Toilets and holding tank

Chemical toilets, or flushing toilets into a sealed tank with manual pump-out.

Standard: Sized to occupancy and days sealed
Life: 15+ years
Checks: Tested in drills

Backflow valves

On every drain, so a flooded or contaminated sewer cannot become a way in.

Standard: Fitted to all outgoing lines
Life: 10+ years
Checks: Annual function test

Living and safety

Food stores

Separate stores for each diet, planned with you. See food.

Standard: FSSAI-labelled products
Life: Ready meals typically 12–24 months
Checks: Rotated before expiry

Medical kit and medicines

Trauma kit, each person's regular medicines and potassium iodide where a doctor prescribes it.

Standard: Planned with your doctor
Life: By expiry date
Checks: Rotated each year

Communications

Radios for official broadcasts in a shielded box, licensed two-way radio, internal intercom.

Standard: Licensed equipment only
Life: Many years
Checks: Tested in drills

Fire safety

Suitable extinguishers, detection and no open flames. Cooking is electric.

Standard: National Building Code of India 2016
Life: Extinguishers serviced yearly
Checks: Annual service

Lighting

LED lighting with a day and night cycle, emergency lights on separate batteries.

Standard: Low heat, low power
Life: 10+ years
Checks: Emergency lights tested in drills

What the world follows

No single international shelter standard exists. These are the national systems engineers most often refer to, and the Indian codes we design to.

Switzerland
The Federal Office for Civil Protection (BABS) issues the TWK 2017 technical guidelines for designing and building shelters, covering structure, air-tightness and loads. Shelter components such as ventilators and doors are type-approved. Switzerland has built shelter space for its whole population.
Finland
The Rescue Act (379/2011) and its 2011 decrees require shelters in larger buildings. Standard S1 shelters have doors and valves rated to 1.0 bar, carry the collapse load of the building above, use NBC filtration with hand cranks, and must be inspected at least every 10 years.
United States
UFC 3-340-02 sets methods for designing structures to resist explosions. FEMA P-361 covers tornado and hurricane safe rooms. Cold War public fallout shelters used a minimum protection factor of 40, far below what a modern private shelter targets.
Israel
Since the 1990s, new homes have been required to include a reinforced protected room, a model for quickly reachable protection inside a building.
Filters, everywhere
HEPA filters are classified under EN 1822 and ISO 29463. H13 and H14 classes are standard for shelters.
India
There is no dedicated Indian standard for private shelters. We design to IS 456, IS 13920, IS 1893, IS 4991, IS 3370 and IS 6313 and the National Building Code 2016, follow NDMA guidance, and benchmark performance against the Swiss guidelines.

How long it takes

A typical Keep shelter on an accessible site, after approval. Larger, rocky, wet or remote sites take longer.

Stage	Typical duration	Notes
Site assessment	2–4 weeks	Soil and groundwater tests, survey, approvals review
Design	4–8 weeks	Structural, life support, layout. Long-lead items ordered at the end of design.
Approvals	1–6 months	Depends entirely on the authority
Excavation and shoring	3–8 weeks	Rock and high groundwater extend this
Raft and waterproofing	2–4 weeks
Walls and roof	6–12 weeks	Concrete pours in stages, with curing time
Doors, valves, services	4–8 weeks	Blast doors and filters arrive 8–16 weeks after order
Backfill and earth cover	2–4 weeks	Compacted in layers
Fit-out	3–6 weeks	Stores, finishes, cover function
Commissioning and drill	2–4 weeks	Pressure test, filter test, full-load power and cooling

Overall: 4 to 6 months for a Haven, 6 to 9 for a Keep, 9 to 14 for a Citadel and 12 to 24 for an Estate, after approval. Remote mountain sites add seasonal limits. See retreat shelters.

Ask for the specification sheet for your site.

After the site assessment you receive a full component list, with the standard and rating for each part.

Start a confidential enquiry