8/2/2019 Column Cast Iron Radiators

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Choosing column cast iron radiators to match your heating requirements

Radiators as part of central heating systems transfer heat or thermal energy, usually from heated

water or gas to air, for the purposes of heating living spaces. The term radiator is not strictly

accurate as they do not transfer energy by thermal radiation but rather by convection. No matter

what we call them though their importance to us is based on how well they can heat the spaces we

live in. Radiators circulate fluid through sections or pipes and have columns to increase their surface

area to allow for the diffusion of heat.

Cast iron radiators are made up of sections joined by threaded nipples and each section in turn is

divided into columns. These columns can vary in number and include 4 and 9 column cast iron

radiators. The manufacture of the 4 column cast iron radiators as an Ideal Standard occurred in the

United Kingdom until the 1970s and is therefore the most likely to be found in older buildings. They

are often preferred by architects and clients wanting to use traditional cast iron radiators since they

provide the retro feel but are also economical. The period preceding the 1970s also saw the use of 9

column cast iron radiators in spaces where height restriction was a factor. For those of you

renovating a period house these radiators add just the right touch.

Radiator heat output is measured in Watts or British Thermal Units (BTUs) and they represent the

same thing although they use different scales. To convert an output measurement in BTUs to Watts

you should divide by 3.412. Retailers will usually specify the output of the radiators they sell and you

will have to determine what your heating needs are prior to making a purchase or consult an expert.

Usually there is a discrepancy between the heating requirement and the radiator output so one

would need to purchase a radiator or radiators that exceed the heating requirement and use

thermostatic valves to regulate the temperature.

When purchasing a radiator you would also come across the term delta T. The delta () T value

indicates the difference in temperature between the water circulating in the central heating system

and the temperature of the surroundings also known as the ambient temperature. The temperature

of the central heating system running in your house is usually around 80C, while you would

generally like to heat your house to around 20C. Calculation of the Delta T value would therefore be

80-20 = 60. In the United Kingdom outputs are usually shown at operating temperatures using delta

T60.

Knowing the various specifications and terminology associated with column cast iron radiators is a

quick way to match your radiator to your heating requirements.