Safety standards are forcing a move from traditional open flame pipe jointing, but is there an effective alternative? David Ward explains how to join the heat-free way.
At first sight the imposition of heat-free jointing in building services, heating and associated pipework contracts looks like bad news. The industry has relied for many years on open flames to achieve soft or hard soldered and welded joints. And these have been the most common methods of achieving sound joints, on which a major proportion of the industry is based.

The heat-free solutions now becoming available however, point the way to more effective means of installing a variety of systems and obtaining major productivity gains.

So where did the emphasis on heat-free spring from? For many years few precautions were taken when using naked flames on pipework installations. This can no longer happen as the increasing demands of Health & Safety measures and the need to conduct safety audits has forced a significant rethink in all sectors of the pipeline industry and their client base. Now most major contracts impose rigid safety conditions around the use of open flame working.

To someone with many years of experience these new safety measures may seem excessive, but there are many advantages in using jointing systems that overcome this problem while allowing the use of traditional pipework materials.

These new jointing methods use copper tube and bring rapid installation methods to the provision of hot and cold water, heating and refrigeration systems.

They remove the need for blowtorches; welding torches; cutting and screwing machines; tube grooving machines; solvents; and fusion equipment.

The systems also allow work on existing pipework in the presence of residual moisture. Upon completion, a perfectly clean tube bore is achieved.

Using heat-free jointing systems provides:

  • major productivity gains for the mechanical services engineer;
  • a cleaner and neater system for the designer;
  • a safer work station to satisfy the safety officer;
  • delivery of a lower cost, cleaner installation in a shorter period of time.

    Heat-free options
    What then are the jointing options open to the contractor and what effects do they have on costs? There are now three options for copper tube work:

  • compression fittings – the traditional heat-free alternative to soldered fittings;
  • push-fit fittings – developed to provide rapid jointing with copper and plastics pipes, push-fit has become equally useful in heat-free situations;
  • press-fit fittings – becoming the preferred method on large-scale contracts thanks to its speed and range of fittings.

    But how do the costs of these methods compare with those of soldering? To give as simple a comparison as possible, the costs and times (shown respectively in the table, right, and graph, right) do not include the additional costs of supervision or other work to comply with open flame working requirements. The costings are based on a chilled water installation in an actual commercial building.

    Looking first at jointing times in the graph below, it can be seen that across the range of fitting sizes, press-fit and push-fit types give lower values. On the larger fitting sizes this reduction becomes significant.

    If the cost of the fitting is factored into the total costs across the typical installation, the press-fit and push-fit types are shown to give an advantage. If the additional costs of complying with hot working certificates are included, the benefits of the heat-free options are even greater.

    Downstream benefits
    Apart from the direct cost saving of the fitting time, contractors have found three major downstream benefits of push-fit and press-fit jointing.

    Cleanliness of the process is a major plus for two reasons: first, no fluxes, resins or adhesives are involved, reducing flushing times and the risk of sensitive equipment, pumps or valves becoming fouled.

    Second, it is possible to guarantee that the pipework contains no lead, as solder, leaded or otherwise, is not involved. Recent experiences in housing schemes have highlighted this as an area where the new Water Regulations have shown their effectiveness.

    On many larger schemes off-site assembly or prefabrication is being used to rationalise installation times. Press-fit and push-fit joints both aid prefabrication.

    Press-fit allows assemblies to be made dry and then rapidly joined on site, with each completed joint instantly giving rigidity and security to the assembly.

    Push-fit joints can be connected and disconnected quickly, as often as required, giving flexibility at the final assembly stage. They also aid the rapid pressure testing of sections of pipework as the work progresses.

    This leads to the third useful feature: where pipework is still wet, both types of joint can be used without having to wait for it to be dried. This is particularly useful for work on existing systems or for temporary connections.

    Many contractors see the challenge of heat-free working as a spur to increase working effectiveness. Far from cutting productivity, they have found it can be increased and a better final product can be produced.

    The heat is on

    Halfords, the car spares retailer, refurbished its head office in Redditch during 2000, with Hilton Building Engineering Services of Nottingham providing the mechanical services. Hilton faced two main challenges, as Halfords wanted to use the floors of the building not under renovation while the work was in progress. First, they had to keep exactly to the building timetable for the floor under renovation. Second, all jointing had to be heat- free to comply with Health and Safety requirements. To satisfy these specifications, IMI Yorkshire PressFit fittings were chosen for the main services of hot and chilled water to the heating and air conditioning outlets. The company’s Tectite PushFit fittings were applied in the final connections to the units. In a second case study, Slough Borough Council renewed the heating systems in four sheltered housing schemes. Installing heating in the schemes, which involved some 110 homes, posed a problem for the Borough and its contractor G H Marshall of Reading: it was impractical to vacate the homes so the installations had to be completed quickly, while posing no safety risks to the occupants. For example, the homes are equipped with fire alarms and the Borough housing staff did not want to turn these off during the contract. IMI Yorkshire PressFit was chosen due to its heat-free jointing process and speed of installation. The new copper jointing system met the requirements for the contract in both safety and speed of installation.

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    Electrical and Mechanical Contractor

    Postscript

    David Ward is national contract sales manager for IMI Yorkshire Tube & Fittings.

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