Blast Door Load Calculator
Enter a peak reflected overpressure (or derive it from a charge + standoff preset) and the leaf area — and get the indicative total blast force (kN) on the door and an indicative class band. Indicative India 2026 only — a real blast door is engineered by a qualified blast/structural consultant.
Indicative only — not a design. Blast doors are project-engineered to ASCE / US ACI 370R (or equivalent) by a qualified blast/structural engineer using the actual charge, standoff, reflected pressure–impulse pair and dynamic structural response. This tool gives a back-of-envelope force and class band only. Never size, buy or sign off a blast door from this output.
Blast load
≈ 7.3 psi. Drag for a feel; type exact values for > 300 kPa.
Typical mid-range event; partly dynamic, partly quasi-static (DLF ~1.3). Leaf 1.2 × 2.4 m = 2.9 m². Force on leaf = overpressure × area (1 kPa = 1 kN/m²). Indicative India 2026 — confirm everything with a blast engineer.
Indicative total blast force on the leaf
0 kN
≈ 15 tonnes-force · 50 kPa over 2.9 m²
Indicative door-class band
Medium
Moderate threat. Reinforced leaf, multi-point bolting and a designed frame/anchorage system.
Overpressure
50 kPa
7.3 psi
Force on leaf
144 kN
press. × area
Design force*
187 kN
DLF 1.3
Force on the leaf vs overpressure at 2.9 m². Dot = your point; dashed lines = class boundaries (35 / 70 / 140 kPa). Indicative only.
Indicative class bands by peak reflected overpressure
A rough robustness tier only. Real classification (e.g. GSA / ASTM F2247 levels, or a project performance spec) is set by the blast engineer from the pressure–impulse pair, not pressure alone.
Low
0–35 kPa
Light blast / nuisance pressure. A hardened steel door with engineered anchorage may suffice.
Medium
35–70 kPa
Moderate threat. Reinforced leaf, multi-point bolting and a designed frame/anchorage system.
High
70–140 kPa
Serious threat. Heavy blast-rated assembly, dynamic-tested, with capacity-designed surround.
Severe
> 140 kPa
Severe / close-in threat. Bespoke blast door + structural surround; full dynamic analysis essential.
Brief a blast door the right way
DesignAI turns this indicative load into a vendor-ready question set — standard, rating, leaf build-up, frame anchorage and what your blast engineer must confirm.
Assumptions & method
*Force on leaf = overpressure × area. Because 1 kPa equals 1 kN/m², the indicative total static force is simply peak reflected overpressure (kPa) multiplied by leaf area (m²). The design force applies a crude dynamic load factor (DLF) for the chosen impulse band to hint at the dynamic amplification — a real design uses the pressure–impulse diagram and an SDOF/FE response, not a single DLF.
The charge + standoff presets give banded, illustrative TNT-equivalent overpressures only — they are not Kingery-Bulmash or UFC 3-340-02 design curves. Class bands (low <35, medium 35–70, high 70–140, severe >140 kPa) are an indicative robustness tier for early conversations.
These doors are project-engineered. Get a vendor spec and a qualified blast/structural engineer (to ASCE / US ACI 370R or equivalent) to size the leaf, frame, hinges and anchorage. Do not procure from this estimate.
Supply costs for blast-resistant doors in India run roughly ₹15,000–₹1,00,000+ per door (supply-only, before 18% GST), rising sharply for severe-band, certified or large openings. Add frame, anchorage, installation and GST.
Related Guides — Deep-dive reading
Blast-Resistant Doors: Overpressure Ratings & Cost India 2026
How blast-proof doors are rated by peak reflected overpressure, impulse and rebound — plus where they are used and what they cost in India.
Home Doors & EntrancesSpecialty Door Cost in India: Price Bands Guide (India 2026)
Indicative ₹ cost bands for fire, blast, bullet, lead, cleanroom, freezer, high-speed and other project-engineered doors in India.
Home Doors & EntrancesEmergency Exit Planning in India (2026): Number of Exits, Travel Distance & Two-Way Escape
The building-scale means of egress that a home escape plan sits inside: why you need two independent, remote exits, how travel distance and exit width scale with occupant load, and why exits must open outward, discharge to safety, and never be locked.
SecurityRelated Tools — You may also find these useful
Acoustic Door STC Calculator
Work out the STC rating and door build — single leaf, drop seal or sound-lock — to hit your target noise level.
STC CalculatorBulk Door Order Estimator
Estimate a builder project door order with volume-discount tiers, city index and 18% GST.
Bulk EstimatorCity Door Price Comparison
Compare the same door across multiple Indian cities side by side and find where it is cheapest.
Price Comparison