TT Talk - Storm preparedness
Climate change is resulting in an increase in the severity of droughts, fires and floods in many parts of the world. Record rainfall resulting in flooding in Eastern coastal areas of Australia are a poignant example. Severity and broader distribution of windstorms can also be attributed to climate change.
TT recently spoke at a Port Technology International (PTI) event in collaboration with Vaisala, recognising the breadth of challenges presented by climate change to the global port and terminal sector. The panel considered a variety of risk exposures including flood, tidal surge and wind microbursts.
Meteorological capabilities have improved in recent years, and Vaisala (amongst others) provide innovative climatic measurement solutions to assist operators in mitigating risk, which can afford opportunity to develop understanding of local climatic conditions. A combination of the ability to ‘now cast’ and forecast underpins data driven decisions linked to risk mitigation strategies, such as when to cease operations or take action to protect property and assets.
Quay crane risks
Due to their size, profile and location on the quayside, quay cranes are particularly susceptible to wind. Care must be taken in the design and operating procedures to protect cranes being blown over or along the rails.
TT Club urges terminals operating quay cranes to review their equipment and emergency plans in respect of high wind situations
TT Club urges terminals operating quay cranes to review their equipment and emergency plans in respect of high wind situations. Of concern to TT is an understanding that many quay cranes are not specified at the procurement stage with both storm pins and storm tie-downs. These safety components are necessary to secure quay cranes adequately during windstorms.
While deployment of meteorological technology to monitor and predict storm events is important, there are a number of safety components available for quay cranes addressing the risks relevant to procurement decision-making. Each mentioned here is optional, rather than being standard equipment, and may not be included in the procurement specification.
- Storm pins are vertical sliding pins mounted at suitable positions under each leg of the crane. These pins are dropped into sockets set into the surface of the quay. The pins must be interlocked with the travel motion so that the crane can only be moved when the pins are disengaged.
- Storm tie-downs are connections on the crane, normally at the four corners, where suitable slings, chains or bars of appropriate size and number can be fitted to connect to anchor points in the terminal pavement. These anchors must be able to hold the loadings of the crane under potential wind conditions.
- Storm or parking brakes can be used between normal operations to avoid the need to apply storm pins or tie-downs. These may be rail clamps or railhead brakes, typically operating as static brakes, i.e. applied only when the crane has stopped moving, intended to help prevent a stationary crane from being pushed along by the wind.
- Wheel brakes should also be installed and maintained, normally being disc brakes mounted on the crane wheels. These are required since rail clamp and railhead brakes are not to be applied when the crane is moving (both the brakes themselves and the crane rail can be damaged).
- Finally, the service braking system acts to slow and stop the crane during normal operations, typically as part of the motor and gearbox.
Storm brakes are not intended as an acceptable alternative to storm pins and storm tie-downs. These safety components are designed to work in tandem to protect the asset. While terminal quay cranes typically include storm-pins, many do not have storm tie-downs. Incident experience has repeatedly demonstrated that storm pins, activated prior to the windstorm, have prevented the crane being blown along the quay, but the crane has still been blown over because storm tie-downs were not in place or deployed.
Storm brakes are not intended as an acceptable alternative to storm pins and storm tie-downs
Decision-making for storm protection is generally based on the maximum wind speed recorded at the destination. Reassessment is prudent, particularly where existing cranes do not have both storm pins and tie-downs installed, to ensure that wind speed measurements used for the maximum uplift calculations during initial design remain valid. Further, second-hand or modified (height increased and/or boom extended) quay cranes are particularly susceptible; wind and uplift calculations should be checked to ensure the storm pins, tie-downs and civil works are structurally adequate.
Importance of maintenance and training
Of course, installing safety components is only the start of the story – robust procedures and training as to how and when to deploy are vital, as is maintenance. Thorough maintenance of these components and the supporting infrastructure is critical to ensure that they operate as expected and remain fit for purpose.
Whether faced with a wind microburst or simply preparing for a forecast approaching storm, storm pinholes being blocked, brake components not having been maintained or crane drivers not being sufficiently trained, will serve to exacerbate the risks faced and potentially result in greater losses.
Call to action
Wind damage to cranes can result in serious injuries to workers and be very costly in repairs and operational downtime. One of the overriding themes to come out of the PTI event was a recognition that climatic conditions are changing and weather patterns becoming less predictable.
Risk assessments need to be kept fresh; do not rely on work conducted several years ago. Be alert to any shift in local climatic conditions in order to take remedial action, protecting the operation, property, assets and, importantly of course, people. Further, TT would strongly recommend consideration of these safety features as a minimum standard for quay cranes, regardless of the intended operational location.
Risk assessments need to be kept fresh; do not rely on work conducted several years ago
If you would like further information, or have any comments, please email us, or take this opportunity to forward to any others who you may feel would be interested.