Stelrad LSTI Plus K2 low surface temperature radiator 500 x 650mm

Low surface temperature (LST) radiators are radiators enclosed in a steel casing, so the surface you can touch stays at or below 43°C even when the heating runs at full design output. They are used where vulnerable people could touch or lean against a hot radiator, such as care homes, hospitals, sheltered housing, schools, nurseries and children's rooms.

How they are built

Inside the casing sits a steel panel radiator, called the emitter. Air passes through grilles in the casing, and the casing also hides the pipework and valves. Casings are usually held by security screws, so they can be lifted off for cleaning, maintenance and decorating but are hard to tamper with. Emitters are made and tested to BS EN 442.

Sizes and heat output

• Casing size: ranges are listed by casing height and length. Deeper models hold a larger emitter and give more heat from the same wall space.
• Heat output: quoted in watts and Btu/h, usually at a mean water to air temperature difference (delta T) of 50°C. At lower system temperatures the output drops considerably, so check the figure at the delta T your system will run at.
• Fitting space: allow a small gap above the finished floor so the casing can be removed later.

Valves and controls

Because the valves sit inside the casing, thermostatic control needs a kit made for LST radiators: a valve head mounted through the casing on a capillary, a remote sensor, or a wall-mounted remote adjuster. Each kit suits particular connection positions, so check the pipe layout first.

For standard radiators, see panel radiators, or browse the wider range of radiators and accessories.