Enjoying the benefits of prefabrication
The more you look into the benefits of packaged boiler plant, the more you find. Paul Sands shares his ideas.
As in every market sector and sub-sector today the multiplicity of choice can be bewildering. When heating and hot water provision are considered, however, much can be said for factory-built packages which resolve many of the actual and potential on-site difficulties. Combining high-efficiency boilers and plate heat exchangers in a fully modulating package can minimise running costs and yield attractively short payback periods. In addition, it pays to look out for boilers which are listed within the Government’s Enhanced Capital Allowances Scheme. One of the major headaches with traditional on-site installation is the need to utilise skilled manual labour intensively. Pre-assembly is less labour-intensive and also saves on costs, which is subsequently reflected in prices paid for packaged plant. Another big advantage of packaged supply is the saving of space which can be used for other purposes. This applies whether compact, skid-mounted or fully enclosed packages are chosen. The latter can often be sited outdoors or, with a relatively lightweight boiler, on a roof. taking up no internal building space at all. A third set of plus points is the obviation of any need for other trades to be involved, with timings to be arranged and kept to, the risks of damage by such workers, and the potentially even more awkward risks of litigation by way of claims or maybe counter-claims. Next in a long list of advantages is speed. If scheduling is planned efficiently, a plant package can be dropped in and begin working within a few hours, before any existing plant is decommissioned. In contrast a smooth, uninterrupted transition can be more difficult to achieve with alternative replacement approaches, especially in adverse weather conditions. Delivery can take as little as six to eight weeks from order acceptance, and even 10 to 12 weeks may well be acceptable in view of the many benefits of pre-packaging. And as for size, all site conditions and requirements are, of course, given due consideration, with a vast range of boiler sizes and outputs to select from. Any British Standard colour or finish can be provided in a pre-assembled plant package. Whether an enclosure casing is finished in a brick-effect or coated steel, it can be made to match any building, or part of any building, on site. If an existing flue has become impractical or unsightly, a flue dilution package can be provided. Connections for pipework are made easy for operatives on-site to work with. Commissioning can be carried out by the supplier of the packaged plant, ensuring it is done correctly and the equipment operates as intended. With lockable enclosures, ingress of dust or water is prevented, and commissioning is made simpler. Flexibility for possible future site changes can be vital, and a packaged system can be designed to be mobile. In other words, the entire heating and hot-water plant can be easily relocated if and when required. Experience matters, of course, as does quality — which means clients, consultants or contractors not only need to liaise with manufacturers at the earliest stages of a project, but should also choose a manufacturer which applies a high degree of technical expertise and uses the best, most durable materials. Buying plant and getting it installed may appear to complete a project, but after-sales service can be important later. Regular servicing and, if advisable, checking for any necessary adjustment, help maintain maximum efficiency throughout a plant’s working life. There is also a possibility, however unlikely, of breakdown, so service and maintenance packages should be available from the plant manufacturer. Operational characteristics can be significant, both in terms of costs and convenience. One example is noise. If the plant operates quietly, there will be no need for expensive acoustic insulation, its cost or the labour needed to install it. Packaged heating and hot water plant can be tailored to suit the requirements of a wide variety of industrial, commercial and institutional buildings or complexes of buildings. The example below is taken from a quote for supplying such packaged equipment to a school. For this project, a packaged, skid-mounted package has a total heat output of 330 kW. The frame was delivered to site in four sections for installation against plant-room walls. The package comprises three 110 kW condensing, modulating, gas-fired, pre-mix, ultra-low-NOx boilers, complete with boiler primary pumps and sequence controller. Also included are isolating valves, check valves, heating flow and return manifold pipework up to and including low-loss vertical header, gas and condensate pipework manifolds, electrical work to connect primary pumps to boilers and controller, and , finally, transport to site. Quotes for packaged boiler plant can be broken down into detailed parts, with, for example, separate quotes for the following • Commissioning. • Site bolting together of sections. • Pressurisation set complete with run/ standby pumps and expansion vessel — together with delivery and commissioning. • DHW plate heat exchangers with primary and secondary pumps, 4-port mixing valves and electronic control panel, all pre-piped and pre-wired, plus delivery and commissioning. • Direct on-mains unvented supply kits comprising adjustable-inlet, pressure-control valves, pressure gauges, check valves, expansion valves and expansions vessels. Paul Sands is with Stokvis Energy Systems
