Free tool · AS/NZS 1170.2:2021 · NCC 2022

HVAC Screen Wind Rating Calculator

Work out the design wind pressure a rooftop or ground-level screen has to be rated to, for screen heights 1.2–3.0 m, then check your supplier's rating against it. A screening estimate to sense-check supplier claims — not a certification.

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Inputs

Find site by suburb or postcode

A B1 B2 (cyclonic)C (cyclonic)D (cyclonic)

Simplified, indicative map — click a dot to pick a town. Region boundaries (coastal 50/100/150 km strips) must be checked on AS/NZS 1170.2 Figure 3.1(A).

LocationIndicative region B1 — SE Queensland, non-cyclonic Region B1. Verify on the AS/NZS 1170.2 wind map.

Region overrideUse for custom sites, or when the engineer confirms a different region.

Importance levelOf the building the screen is attached to. Level 2 is typical.

Selected: Ordinary (most jobs) — Houses, offices, shops, apartments, warehouses, factories. Pick this unless the building fits Level 3 or 4.Which should I pick?

Level 1 — Low consequence: Farm sheds, minor storage, buildings rarely occupied. Rarely right for HVAC screens — only use if the engineer confirms.
Level 2 — Ordinary (most jobs): Houses, offices, shops, apartments, warehouses, factories. Pick this unless the building fits Level 3 or 4.
Level 3 — High occupancy / major: Schools, childcare, large shopping centres, aged care, stadiums, buildings holding lots of people. Higher design wind.
Level 4 — Post-disaster / essential: Hospitals with emergency/surgery, police, fire, ambulance, emergency control centres, critical utilities. Highest design wind.

Not sure? Go one step more conservative (higher importance, lower terrain number) and have the engineer confirm.

Terrain categoryClause 4.2.1. 2 is a conservative default; smoother terrain (1) increases load.

Selected: Open country (safe default) — Open paddocks, golf courses, grassland with few scattered trees or buildings, most new estates on the fringe. Conservative choice when unsure.Which should I pick?

TC 1 — Very exposed: Open water, beachfront, mud flats, bare plains, airfields. Highest wind — use for coastal frontage.
TC 2 — Open country (safe default): Open paddocks, golf courses, grassland with few scattered trees or buildings, most new estates on the fringe. Conservative choice when unsure.
TC 3 — Suburban: Established suburbs, houses ~10 per hectare, light industrial estates. Lower wind — confirm surrounding cover in every direction.
TC 4 — City centre: Dense CBD with many tall buildings (10 m+) close together. Lowest wind — rarely justified; neighbours can be demolished.
TC 2.5 — Developing / light suburban: Outer suburbs with sparse houses, rural residential, some trees. Only if the site clearly sits between open and suburban.

Not sure? Go one step more conservative (higher importance, lower terrain number) and have the engineer confirm.

Roof height above ground H (m)Measure from ground to the roof surface the platform or screen sits on — NOT to the top of the screen. The calculator adds the deck height (in the design tool) and the screen height itself to check pressure at the top of the screen. Enter 0 for a ground-level screen.

Supplier rated pressure (kPa, ultimate)From the supplier's engineering data, for your fixing and post spacing. Leave blank to skip the check.

Zone the supplier rating covers

Engineer has confirmed the wind region (B1) and terrain on the official map.Screen is close to a roof edge or corner (local pressure increase not included here).

Advanced factors (engineer values)

Md direction1.0 required for cladding in B2, C, D.

Ms shielding1.0 = no shielding.

Mt topographic1.0 = flat site.

Cdyn1.0 for rigid screens.

Cp,n generalScreening value 1.3.

Cp,n end / cornerScreening value 2.3.

Kp porosityKeep 1.0 unless the engineer justifies less.

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Calculated wind results

Screening estimates from your inputs — not an engineer-approved rating.

Wind region

Non-cyclonic

Return period

500 yrs

Importance level 2

Regional wind speed (V_R)

57 m/s

Climate multiplier (Mc) 1

Calculated pressures · 3.0 m screen

General zone

2.69 kPa

End / corner zone

4.76 kPa

Check these pressures with your supplier and engineer. Ask the supplier for an ultimate wind-pressure rating for the complete screen system, including posts and fixings. The engineer must confirm the required pressures and which zones apply.

These figures are for a 3.0 m screen only. For your actual screen height, use the matching row below and provide its pressures, shear and base moment to the supplier and engineer.

• Wind region and terrain are indicative only until the engineer confirms them on the map.

Screen h	Top z	Mz,cat	V_des	q	p general	p end/corner	Shear	Base moment	Use gen / end	Check
1.2 m	11.2 m	1.012	57.7 m/s	2.00 kPa	2.60 kPa ≈ 265 kg/m²	4.59 kPa ≈ 468 kg/m²	3.11 kN/m	1.87 kNm/m	—	Enter supplier rating
1.5 m	11.5 m	1.015	57.9 m/s	2.01 kPa	2.61 kPa ≈ 266 kg/m²	4.62 kPa ≈ 471 kg/m²	3.92 kN/m	2.94 kNm/m	—	Enter supplier rating
1.8 m	11.8 m	1.018	58.0 m/s	2.02 kPa	2.63 kPa ≈ 268 kg/m²	4.65 kPa ≈ 474 kg/m²	4.73 kN/m	4.25 kNm/m	—	Enter supplier rating
2.1 m	12.1 m	1.021	58.2 m/s	2.03 kPa	2.64 kPa ≈ 269 kg/m²	4.67 kPa ≈ 477 kg/m²	5.55 kN/m	5.83 kNm/m	—	Enter supplier rating
2.4 m	12.4 m	1.024	58.4 m/s	2.04 kPa	2.66 kPa ≈ 271 kg/m²	4.70 kPa ≈ 479 kg/m²	6.38 kN/m	7.65 kNm/m	—	Enter supplier rating
2.7 m	12.7 m	1.027	58.5 m/s	2.06 kPa	2.67 kPa ≈ 273 kg/m²	4.73 kPa ≈ 482 kg/m²	7.22 kN/m	9.74 kNm/m	—	Enter supplier rating
3.0 m	13.0 m	1.030	58.7 m/s	2.07 kPa	2.69 kPa ≈ 274 kg/m²	4.76 kPa ≈ 485 kg/m²	8.07 kN/m	12.10 kNm/m	—	Enter supplier rating

Ultimate limit state net pressure on the screen. Shear and base moment are per metre of screen run, general zone. AS/NZS 1170.2:2021 · NCC 2022 · data 24 Oct 2026.

What this means

In plain terms: the screen must be rated to at least the pressure shown for your site and height. For example 2.7 kPa is roughly 274 kg pushing on every square metre of screen face.

It's the whole system, not just the panel. Load goes from the louvres or panels into the posts, the base fixings, then the platform or roof. A strong panel on weak fixings still fails — the shear and base moment are for the fixings.
It's an ultimate load — the rare extreme event. Some suppliers quote a working (serviceability) pressure or a wind speed; ask which, as they aren't directly comparable.
The zone matters. Ends and corners see higher pressure than the middle.
Conditions apply. The rating only holds for the supplier's post spacing, fixing, porosity and mounting.
Wind pushes both ways — front and back.
It's a screening estimate. The engineer's calculation replaces it, including roof edge effects, debris in cyclonic regions and repeated loading of louvres.

Supplier check

Ask the supplier for:

The design pressure (kPa) and whether it's ultimate or working.
Which zone it covers — general, or end/corner along the whole screen.
The post spacing, bracing and fixing type it assumes.
The engineer's certificate or test report behind it.

Enter the supplier's rated pressure to see the heights it covers.

State matrix

Same inputs for every location (region override ignored). Regions are indicative city assignments.

QLDBrisbane (B1)2.66 kPa

QLDGold Coast (B1)2.66 kPa

QLDSunshine Coast (B1)2.66 kPa

QLDToowoomba (B1)2.66 kPa

QLDGladstone (B2)2.93 kPa

QLDRockhampton (B2)2.93 kPa

QLDMackay (C)3.93 kPa

QLDTownsville (C)3.93 kPa

QLDCairns (C)3.93 kPa

NSWSydney (A)1.66 kPa

NSWNewcastle (A)1.66 kPa

NSWWollongong (A)1.66 kPa

NSWWagga Wagga (A)1.66 kPa

NSWLismore (B1)2.66 kPa

VICMelbourne (A)1.66 kPa

VICGeelong (A)1.66 kPa

VICBallarat (A)1.66 kPa

VICBendigo (A)1.66 kPa

SAAdelaide (A)1.66 kPa

SAMount Gambier (A)1.66 kPa

SAPort Augusta (A)1.66 kPa

SACoober Pedy (A)1.66 kPa

WAPerth (A)1.66 kPa

WABunbury (A)1.66 kPa

WAGeraldton (A)1.66 kPa

WAKalgoorlie (A)1.66 kPa

WABroome (C)3.93 kPa

WAPort Hedland (D-WA)6.51 kPa

WAKarratha (D-WA)6.51 kPa

TASHobart (A)1.66 kPa

TASLaunceston (A)1.66 kPa

TASDevonport (A)1.66 kPa

NTDarwin (C)3.93 kPa

NTAlice Springs (A)1.66 kPa

ACTCanberra (A)1.66 kPa

Shaded = cyclonic region. Red border = above the supplier rating entered.

Method & limits

V_des = V_R × Mc × Md × Mz,cat × Ms × Mt (≥ 30 m/s) · q = 0.6 V_des² · p = q × Cp,n × Kp × Cdyn

Verified against published sources: regional speeds, Mc, NCC return periods, Mz,cat values.
Screening values, not from the standard: Cp,n 1.3 / 2.3 and Kp 1.0 — the engineer replaces them for the actual geometry and porosity.
Not included: roof edge/corner pressure increases, parapet or building-induced effects, area or local pressure factors, windborne debris, fatigue.
Wind regions, editions and state variations (e.g. WA Region D) change — confirm the standard in force.
Tall HVAC units on the platform need tie-downs designed for the same wind.

Sources

Sources consulted 24 Oct 2026.