Lifting Approval Workstation · v0.3 · KSATower Crane Wind-Speed Assessment

EN 13001-2ISO 4302BS 7121-5 CIG 2507SBC 301

Load tools ↗

1Project, crane & people

Project

Crane ID cascades

Appointed Person

Operator

Crane type

OEM in-service limit V_limit m/s 3-s

Jib length m

Radius m

Hook height m

OEM source ref

2Operation & load

Operating mode

Hook load m t incl. rigging

Projected area A_p m²

Load shape

Drag C_w

3Site wind

Gust @ boom m/s

Assessment result

DraftSubmittedAP checkedApproved

Enter the lift data and run the assessment. The Live model tab animates the wind and gust against this crane; the Symbols tab defines every variable; the Report tab builds a printable lifting report once submitted.

Variables on this page

m hook load incl. rigging [t]

A_p projected area [m²]

C_w drag / shape coefficient

V_limit OEM in-service limit [m/s]

V_allowed permissible wind speed [m/s]

p wind pressure 0.625·v² [N/m²]

F_H wind force on load [kN]

z height of lift [m]

Live wind model — arrows scale with magnitude & recolour with risk

The grey arrow is the governing limit V_allowed (the ceiling). The live arrow extends with the assessed gust and turns green → amber → red as it approaches and exceeds the limit. The crane is drawn to your jib / radius / hook-height configuration and crane type; the load morphs to the selected shape with size proportional to A_p. Change any value on the Assess tab and this updates live.

Gust vs limit

Configuration factored

Wind force on load — F ∝ v²

Doubling wind speed quadruples force. Marker = assessed gust; dashed = governing limit.

Downrating: V_allowed vs A_p

V_allowed=min(V_lim,V_lim·√(1.2m/A_pC_w)). Marker = current load.

Permissible wind speed — decision flow (BS 7121-1 Annex D-1)

Symbols, definitions & illustrations

How the pieces connect

Wind speed → pressure (square law) → force on the sail area of the load → sideways load into the boom and an overturning moment about the tipping line. The permissible speed downrates whenever the load's sail area exceeds the design allowance of 1.2 m²/t.

Standards in use — what the application applies from each

Standards library — applies to your current inputs · tap any standard for clauses

Run or change an assessment to see which clauses apply.

Governing formulae

p = 0.625·v_s² [N/m²] — ISO 4302 §4

F_H = c_H·A_H·p [N] — ISO 4302 §5.2

A_H = max(0.8, 0.0005·m_H[kg]); c_a=2.4 → 1.2 m²/t

V_allowed = min(V_limit, V_limit·√(1.2·m / A_p·C_w))

v_gust(z)=v_m(z)·√(1+7·I_v) — EN 1991-1-4

q=0.0473·K_zK_ztK_d·V²_[km/h]·I — SBC 301 (out-of-service)

Limit ladder (tower crane)

13.5	Erection / alteration cap — CIG 2507 §5.1.2
14.1	No special load case below — EN 13001-2 Table 1
17	UK structural wind-off (38 mph) — BS 7121-5 §14.1
20	Normal in-service design max — EN 13001-2 Table 1
28.5	Process-crane ceiling — ISO 4302 Table 2
10 min	Return-to-service clear period — BS 7121-5 §14.1.4.2

Saudi Arabia wind environment

Two regimes matter and must not be confused. Extreme / design winds (SBC 301, from Saudi Aramco SAES A-112) govern out-of-service storm-securing — they are 3-s gusts at 10 m for a structural return period (≈42–53 m/s) and are far above any working limit. Operational winds — the daily forecast and the crane anemometer — govern whether a lift may proceed; the dominant operational hazard is the Shamal and its dust storms.

SBC 301 basic 3-s gust @ 10 m (out-of-service design)

City	km/h	m/s	Region

Source: SBC 301 Fig 6.4-1, adopted from Saudi Aramco SAES A-112. Use these to check the crane's out-of-service / storm configuration, not daily go/no-go.

Operational picture & the Shamal

Prevailing Shamal — NW wind, strongest Jun–Jul; raises multi-day dust storms.
Eastern Province (Dammam / Khobar / Dhahran) sits in the direct shamal path — 2–5 day dust events.
Riyadh / central Najd — ≈2–3 dust events per month in peak season, usually briefer.
Jeddah & western coast — sheltered by the Sarawat mountains, least affected; sea breezes dominate.
Dust events reduce visibility and bring gust spikes — a wind-sensitive lift can become a NO-GO well before any structural limit.

Jeddah design

152 km/h

Riyadh design

152 km/h

Dammam design

155 km/h

Shamal peak

Jun–Jul

Worked lift samples — tap to load

From CIG/TCIG 2507 and the project worked examples. Each loads the inputs, runs the assessment and logs it.

Lifting wind-assessment report

Run an assessment on the Assess tab, then submit it. The signed report builds here.

Live weather — Open-Meteo (current wind, gusts & direction)

City

Pulls the current 10-m mean wind, peak gust and direction for the selected city from Open-Meteo (keyless, CC BY 4.0). If the preview sandbox blocks outbound requests, it falls back to manual entry and still works in the deployed/downloaded app. Forecast figures are at 10 m — the engine height-corrects them to a 3-s gust at the crane. Operational go/no-go always uses the crane anemometer as the authority.

Audit log — tamper-evident (SHA-256 hash chain)

#	Time (UTC)	Ref	Crane	Mode	m	Ap	Cw	V_lim	V_allow	Gust	Decision	State	By	Hash
No entries yet.

Each entry binds the previous entry's hash; any later edit, deletion or back-dating breaks the chain and is caught on verification. Integrity flags reject implausible or out-of-bound inputs at the point of entry.