Why Storm Design Matters in Oman and the UAE
Tropical cyclones from the Arabian Sea are infrequent, but when they reach the coast their impact is severe. Cyclone Gonu in June 2007 brought destructive wind, rain and flooding to Muscat and the eastern coast of Oman. Cyclone Mekunu in 2018 struck Dhofar and Salalah. Cyclone Shaheen in October 2021 made landfall on the Al Batinah coast with strong winds and heavy flooding, and its effects reached parts of the UAE.
For glazing, these events combine three loads at once: high wind pressure, wind-driven rain and flying debris. Day-to-day conditions also matter. Coastal towers in Dubai and Abu Dhabi face strong winds at height every year, and shamal events produce sustained gusts across open sites. A window that is only selected for appearance and thermal performance may not be adequate on an exposed elevation.
How Wind Load Is Calculated
Wind load design follows the building code adopted for the project and, for larger buildings, the project's structural engineer. The general method is the same in most codes:
- Basic wind speed for the location is taken from the applicable code or a site-specific study
- The speed is converted to a velocity pressure, which grows with the square of wind speed
- Adjustments are applied for height, terrain and exposure, since wind speeds increase with height and over open sea or flat ground
- Pressure coefficients are applied for the building shape; corners and edges of a facade typically see higher suction than the centre
- Internal pressure is considered, because a broken window or open door can pressurise the interior and increase the net load on other windows
The basic relationship is velocity pressure = 0.5 × air density × wind speed². As an illustration only, a wind speed of 40 m/s gives a velocity pressure of about 1.0 kPa, while 50 m/s gives about 1.56 kPa. A 25% increase in wind speed therefore raises pressure by more than 50%. Design values must always come from the project engineer, not from a rule of thumb.
Frame Strength and Deflection
Once the design pressure is known, each window and door is checked for:
- Profile strength and stiffness: wall thickness, profile depth and any steel or aluminium reinforcement in mullions
- Deflection: frames must not bend so far that glass is overstressed or seals open. Limits are usually set as a fraction of span in the project specification (L/175 is a figure frequently used in international practice) and should be confirmed for each project
- Hardware capacity: hinges, locks and keeps must hold the sash under suction, not only under pressure
Heavier profiles help on exposed elevations. In the Alminyar range, the F16 and Q35 casement windows use a 3.0 mm wall thickness, and the T130-100 sliding door uses a 3.0 mm wall with a heavy-duty roller system. Windows such as the S11, X11 and K90 are catalogued at wind resistance Level 9. Catalogue ratings confirm a tested class; they do not replace a project-specific check of sizes and pressures.
Glass Thickness and Type
Glass thickness is selected from the design pressure, the pane size and its support conditions. Larger panes and higher pressures require thicker glass or a different make-up.
| Glass type | Behaviour under storm load | Typical role |
|---|---|---|
| Annealed (float) | Breaks into large sharp pieces | Rarely suitable on exposed elevations |
| Tempered | Several times stronger than annealed; breaks into small fragments | Large panes, doors, high pressure |
| Laminated | Interlayer holds fragments in place after breakage | Debris risk, overhead and high-rise glazing |
| Laminated insulated unit | One or both panes laminated in a double-glazed unit | Coastal villas and towers needing safety and thermal performance |
Laminated glass is the key choice for cyclone exposure. If debris breaks the pane, the interlayer keeps the glass in the frame, which keeps wind and rain out and limits the internal pressure rise described above. The Alminyar T5 electric lifting window, for example, uses 8+1.9PVB+8 laminated safety glass. In a double-glazed unit, a laminated inner or outer pane can be combined with Low-E glass for heat control.
Anchoring the Frame to the Structure
The strongest window fails if its fixings pull out. Anchoring design should cover:
- Fixing type and spacing suited to the substrate (reinforced concrete, block work or steel)
- Edge distances so anchors do not split blockwork or concrete
- Brackets and shims that transfer load without crushing or allowing movement
- Corrosion protection for all fixings, using stainless steel or coated fixings in coastal locations, and isolating dissimilar metals from aluminium
Fixing layouts should appear on shop drawings and be inspected on site before the perimeter is sealed.
Water Tightness Under Driving Rain
Storms push rain sideways and upwards against the facade. Good water tightness depends on:
- Multiple seal lines with an outer rain screen and an inner air seal
- Pressure-equalised drainage so water in the outer chamber is not driven inwards
- Sill design with upstands and sub-sills that direct water out
- Continuous perimeter sealing between the frame and the opening
Catalogue water tightness ratings (Level 6 on many Alminyar casement systems) indicate performance under laboratory test; site installation quality decides whether that performance is achieved.
Practical Measures for Storm Season
- Close and lock all sashes before a storm warning, so multi-point locks engage fully
- Keep drainage slots clear of sand before the rainy season
- Inspect perimeter sealant after each major weather event
- Store or secure loose items on terraces that could become debris
Alminyar Recommendation
For coastal villas and buildings in Muscat, Sur, Salalah and the UAE coast, we recommend defining design wind pressures with your structural engineer early, then selecting profile series, glass make-up and anchoring to match. On exposed elevations, specify laminated glass, heavier casement profiles and multi-point locking. Alminyar can prepare wind load calculations and shop drawings for review by your consultant.