With commissioning being a vital part of any plant installation process, Steve O’Neill, Technical Specifications Engineer at EOGB Energy Products Ltd provides a step-by-step guide to the correct procedures that engineers must follow…
Many modern appliances depend greatly upon their high efficiency and performance to answer ever more stringent efficiency and emissions criteria, which are currently being placed upon them by changing legislation.
The first step in achieving this is to ensure accurate plant specification and installation for the process at hand. Following this, the equipment must be commissioned in a manner that will confirm that the appliance is operating both safely and at an optimum level of efficiency.
It should be noted that there are legal considerations to be made when it comes to burner/boiler commissioning as it is the responsibility of the commissioning engineer to ensure that all relevant standards and legislation have been adhered to, as they will become the person responsible for allowing the plant to be operated for the first time and consequently left in service.
In order to establish the plant has been installed in compliance with all relevant standards and any specific requirements of the plant manufacturer the commissioning engineer must carry out a visual inspection of the entire installation.
The visual inspection must confirm the provision of and correct installation of:
Once a satisfactory visual inspection of the surrounding components has been completed it is possible to focus on the equipment to be commissioned. Before beginning start-up, the commissioning engineer should consult the installation instructions and understand the sequence of operation and equipment controls. This should include a review of the wiring diagram, and the burner control train including the manufacturers recommended operating variables (for example temperatures, pressures, drafts, relief valve settings and flue gas content).
If any of the above-mentioned criteria are not met then it will not be possible to carry out the commission until all necessary remedial work has been carried out, the installation is fully compliant with all relevant standards and the manufacturers requirements are satisfied.
Prior to start-up some basic electrical checks must be performed in order to confirm the compliance of the controls including the function of any limit and overheat thermostats as well as the correct operation of any safety valves as per the aforementioned manufacturer’s instructions. This can usually be achieved by implementing a battery of preliminary electrical checks with the electric power being isolated appropriately from the equipment being worked on.
Upon completion of satisfactory preliminary electrical tests with no load being applied, the power can be switched on to the equipment allowing for the confirmation of correct polarity. If the plant requires a three-phase supply it is necessary to ensure the correct rotation of the blower etc.
The actual component testing can be unique to a given piece of equipment and it is essential to obtain relevant training from the equipment manufacturer prior to embarking on any commissioning work. It is for this reason that only suitably trained and qualified personnel should perform commissioning work of any description.
A relevant tightness test should also be carried out on the equipment gas train up to the nearest isolation valve. This procedure will vary depending upon the size of the gas train and guidance should be sought from the relevant IGEM documents and British standards. It should be noted that some equipment (above 1200kW) incorporates integrated valve proving and safety shut off valves, which will perform this function prior to every start up.
Upon completion of a satisfactory tightness test it is vital to perform a dry run of the equipment to ensure a fail to safe condition occurs should the gas supply be interrupted at any time or in the event of a component failure. This can also be used as an opportunity to confirm the correct sequence of operation for the equipment as per the manufacturer’s instructions.
In order to achieve both maximum efficiency and optimum levels of safety both manufacturers and engineers understand that there is a close relationship between the volume of combustion air, fuel, and the relevant flue gas temperature as well as the heat input at all stages of combustion. These requirements cannot be confirmed by observing a flame picture alone and it is necessary to measure, analyse and adjust the equipment accordingly using the appropriate testing and measuring equipment to confirm the combustion gas constituents exist in the correct proportion. This procedure can vary considerably depending upon the type of plant being worked on. It is at this stage that all pressure readings are observed to confirm correct pipe sizing and that a sufficient supply of gas is available even under the most exacting circumstances.
Due to the government’s focus on limiting the volume of greenhouse gases entering the atmosphere it is not only the responsibility of the manufacturer but also the commissioning engineer to endeavour to minimise the emission of these gases whilst also ensuring safe, efficient operation of the equipment. By adhering to correct commissioning procedures it is possible to achieve both of these goals.
Once the equipment is set up as per the manufacturers instructions and is operating both safely and efficiently the relevant documentation should be filled out and left on site with the relevant personnel. A demonstration of the plant operation should now be given highlighting any emergency procedures. If the routine maintenance is to be carried out by on site operatives they should be appropriately trained in their task, which should include a written examination about the safe operation and working procedures of the equipment.