How Wattage Translates to Coverage
A flood light's coverage area depends on wattage, mounting height, and beam angle. General rule for a 90° beam flood light: 20W at 3m height: covers ~15 sq.m at 200 lux (good for home gate). 50W at 4m height: covers ~40 sq.m at 200 lux (compound wall). 100W at 5m height: covers ~80 sq.m at 200 lux (small parking lot). 150W at 6m height: covers ~120 sq.m at 200 lux (petrol pump lane). 200W at 8m height: covers ~180 sq.m at 200 lux (factory loading bay). 400W at 10m height: covers ~350 sq.m at 200 lux (sports ground section). For lower lux requirements (50 lux for security perimeter): multiply coverage area by 4.
Application-wise Wattage Table
Home compound gate (3m mounting): 20–50W. Housing society parking (5m mounting): 100–150W per zone. Factory yard / loading dock (8m mounting): 150–200W per point. Petrol pump forecourt (canopy mount): 100–150W per fixture. Petrol pump exterior drive (5m pole): 100W. Cricket/football ground (10m mast, amateur): 400–600W per mast, 4–6 masts. Cricket ground (broadcast quality): 1000W+ per mast, 6–8 masts. Construction site tower light (8m): 300–500W. Billboard / hoarding illumination (5m): 150–300W angled. Cold storage exterior (5m): 100–150W. Warehouse outdoor yard (8m): 200–300W. Agricultural sorting shed (open): 150–200W.
Beam Angle Matters as Much as Wattage
A 100W flood light with a 60° narrow beam is completely different from a 100W with a 120° wide beam. The narrow beam concentrates all light in a small area - very high lux at the centre, dark at the edges. The wide beam spreads light over a larger area at lower lux. For building facades: use 60° narrow beam, angled upward. For open parking and yards: use 120° wide beam, mounted high. For sports grounds requiring uniform illumination: use 60°–80° beams from high masts placed at precise positions (requires photometric design). Xera Tech flood lights are available in 60°, 90°, and 120° beam options.
How Many Flood Lights Do You Need?
Estimate: divide your total area by the single-fixture coverage area from the table above, then add 20% for overlap and edge losses. For a 1,000 sq.m factory yard (200 lux target, 8m poles, 200W lights): 1,000 ÷ 180 × 1.2 = ~7 lights. For a 500 sq.m open parking lot (50 lux, 5m poles, 100W lights): 500 ÷ (80 × 4) × 1.2 = ~2 lights. For precise calculations, request an IES photometric report from Xera Tech - free for orders of 5+ fixtures.
