One extreme to the other

Below-the-hook equipment is often used in environments where extreme temperatures are part of everyday operations, from steel mills to the polar regions, and many end-user markets in between. Caldwell, J.C. Renfroe, and RUD products are regularly used and specially manufactured for such applications.

Depending on the geography and industry, the point at which a temperature is generally accepted to be ‘extreme’ varies. It is therefore important to both consult with manufacturers and refer to relevant standards. For example, ASME (American Society of Mechanical Engineers) BTH- 1 suggests that when the temperature where the lifter, structure, or mechanical component under consideration is working is above 150°F (66°C) or below 25°F (-4°C) we are talking about extremities. ASME also refers to design consideration for electrical components when temperatures do not exceed 104°F (40°C). In Europe, RUD states that normal working temperatures are -40°C (-40°F) to 100°C (212°F), after which point a de-rating factor is applied.

Certain equipment can be used at even greater temperatures. We fulfilled a lifting clamp order for use at 1,000°F (538°C) but the temperature and its impact, especially at extremes, must always be considered. That is why we have our own design criteria for products that fall outside ASME’s 25°F to 150°F range.

With extreme heat, the mechanical property of most materials is greatly reduced; and at extremely cold temperatures, materials become brittle.

We utilise the Charpy impact test to determine brittle failure at cold temperatures. Using a lifter not specifically designed for extreme temperatures could result in an insufficient factor of safety, or failure of the lifter depending on the extreme temperature it is exposed to.

When working in high heat, it is important to use the correct steel type. When heated, high-strength alloys not only lose strength, but chemical properties can be permanently affected, resulting in lower mechanical properties of the material.

When using steels such as A36 or A572 (not high strength alloys), the properties will result in a loss of strength at temperature but not permanent loss of strength when cooled to room temperature.

All things considered, product and material selection are vital; If you need a different spec, that must be achieved during—not after—manufacturing.

If a standard product is going to be used in extremes, the manufacturer needs to review the temperatures the end user operates in to see if the criteria can be met with a standard product. For instance, if a customer wanted a lifter for a 350°F (177°C) environment, this would be reviewed and accepted by Caldwell, but only due to the relatively low temperature it is being exposed to. As with lifting operations in more typical environments, a variety of components are required for safe operations, such as controls and ancillary equipment. It is necessary for each of them to meet the stringent design requirements; a beam with inferior attachments will be just as unsafe as not sourcing the correct product at the centre of the lift.

It is always necessary to pay attention to use, inspection, maintenance, and storage when using below-the-hook equipment; suffice it to say that working at extreme temperatures puts even more emphasis on each of these facets of best practice.

Where snow or ice has settled on a lifter or below-the-hook product, it is advisable to carefully remove it and complete a thorough pre-use inspection.’