THE EFFECTS OF WIND ON CRANES AND THEIR LOADS

1. Houston Business Roundtable – Feb. 12, 2013 THE EFFECTS OF WIND ON CRANES AND THEIR LOADS Matt Gardiner, P.E.

2. Houston Business Roundtable PRESENTATION OVERVIEW • Wind Effects • Standards & Regulations • Wind Related Accidents • Lift Planning Considerations • Questions

3. 1 Wind Effects

4. 1 WIND EFFECTS About wind… • Wind speeds are measured at 33 feet above ground • Wind speed increases with height • Gusts can be a bigger problem than sustained winds • Look for obstructions to wind • Look for potential areas that funnel or redirect wind

5. 1 WIND EFFECTS How does wind affect a lift? • Wind applies forces directly to the load (sail effect) • Wind applies forces directly to the crane • Drift can cause tip-overs or side-loading • Drift can eliminate clearances with boom or other obstructions • Drift (inward) can cause backward instability • Wind on load can cause load control issues

6. 2 Standards & Regulations

7. 2 OSHA Regulations STANDARDS & REGULATIONS • Crane manufacturers, OSHA and ASME provide wind requirements • §1926 Subpart CC • §1926.1403(h)(12) and §1926.1435(b)(4)(iii): Wind effects must be considered during A/D ops for mobile and tower cranes • §1926.1410(c)(1): Power line drift from wind when working inside Table A distances • §1926.1417(h): Equipment securement requirements from storm warnings • §1926.1417(n): Capacity adjustment requirements due to wind • §1926.1431(k)(8)(i): Personnel hoisting requirements – 20 mph at the platform? • §1926.1435(e)(6)(v) and §1926.1437(e)(3): Wind indicators required on tower cranes and cranes on barges • §1926.1437(m)(1)(ii): Load charts must consider 40 mph winds for cranes on barges • §1926.1437(n)(1)(i): Rated capacity reduction requirements (as applicable) due to wind for cranes on barges

8. 2 ASME Standards STANDARDS & REGULATIONS • ASME B30.5 - 2011 • 5-3.1.3.2.1(h)(2): Site Supervisor responsible to ensure potential effect of wind is addressed • 5-3.2.1.5(b)(5): The effect of wind on the load and crane has to be noted and considered • 5-3.4.5.4(g): For operations within a FULLY ERECTED/EXTENDED BOOM LENGTH of Table 5-3.4.5.1-1 (same as OSHA Table A), horizontal and vertical power line drift due to wind shall be added to the minimum clearance distance in the Table • Also requires consultation with utility owner to get specific clearances

9. 4 LIFT PLANNING CONSIDERATIONS

10. 4 LIFT PLANNING CONSIDERATIONS What does the manufacturer say? • Most manufacturers recommend capacity reductions above 20 mph • Most manufacturers set maximum allowable wind speeds for operations • Always consult the operations manual for instructions

11. 4 LIFT PLANNING CONSIDERATIONS What is the wind forecast? • Check with reliable sources (NWS, NOAA, official stations) • Look for peak projected sustained and gust speeds AND wind direction(s) • Speeds tell you how much force can be applied • Direction tells you how the crane and load will be loaded by wind • Remember that wind forecasts are at a height of 33 feet and your cranes and loads may be much higher

12. 4 LIFT PLANNING CONSIDERATIONS Food for thought • Will the wind generate enough force to significantly move the load? • Will the wind generate enough force on the crane’s boom to jeopardize stability? • Can the wind cause load control problems? • Are there nearby buildings that can funnel or redirect wind flow? • Has the Operations Manual been consulted for limitations? • Is there anything nearby that can be affected by wind that could interfere with the lift? • Are there any on-site weather stations or anemometers?

13. 4 LIFT PLANNING CONSIDERATIONS References • OSHA Regulations • ASME Standards • Crane Manufacturer (Operations Manual) • Cranes and Derricks, by Howard Shapiro

14. 5 QUESTIONS?