Boilers are pressurised systems that heat a fluid and deliver it to a facility to meet its thermal energy requirements. They operate by transferring heat from a fuel-burning or electrical system to the fluid.
Boilers are classified by the fluid they use and further categorised by their fuel system. For example, a system using oil is called a thermal oil boiler, one producing steam is a steam boiler, and one using hot water is a hot-water boiler.
All safety components must be checked for correct operation. Boilers also undergo pressure testing to verify safe operation under pressure. There should be no pressure loss, leakage or deformation at the end of the test.
Boilers
Boilers are heat-generating equipment operating at elevated temperature and pressure. They are classified according to the working fluid, construction, shape and combustion-chamber pressure.
By working fluid:
– Hot-Water Boiler
– High-Temperature Hot-Water Boiler
– Thermal Oil Boiler
– Steam Boiler
By construction:
Cast-Iron Boilers (Sectional)
Steel Boilers
By boiler shape:
Semi-Cylindrical Boiler
Fully Cylindrical Boiler
Prismatic Packaged Boiler
By combustion-chamber pressure:
Pressurised-Furnace Boiler. Periodic inspections were first addressed in the Occupational Safety Regulation published in 1973. They were subsequently covered in greater detail by Occupational Health and Safety Law No. 6331, published on 20 June 2012, and the associated Regulation on Health and Safety Requirements for the Use of Work Equipment, published on 25 April 2013. The framework addressed matters not previously covered and introduced a broader perspective on periodic inspection. The regulation established a more professional approach, and progress in this field has continued.
Significant changes were introduced by the Regulation Amending the Regulation on Health and Safety Requirements for the Use of Work Equipment, published on 18 February 2022. These changes include:
- Following major maintenance or repair, and during third-year inspections, boilers must undergo a hydrostatic test at 1.5 times the pressure vessel's maximum working pressure or at the pressure stated on its nameplate. Where the relevant standard specifies otherwise, that standard must be followed. During first- and second-year inspections, hydrostatic testing must be carried out at the equipment's operating pressure.
- The justification for any non-destructive examination must be included with the periodic inspection report. The person performing the examination must hold Level 2 certification to TS EN ISO 9712. The selected method must be one offered as an alternative to hydrostatic testing in the pressure vessel's periodic inspection or manufacturing standard.
- Boiler inspections take account of the standard applicable in the year of manufacture. If the equipment can be brought into conformity with the current standard, the current standard should be used. If no standard existed in the year of manufacture, the first published standard should be applied.
A steam boiler produces steam. Steam boilers can use fossil fuels such as natural gas, coal and fuel oil as their heat source.
Steam boilers are widely used in industry. Types include shell or fire-tube boilers and water-tube boilers.
The type of steam boiler is selected according to factors such as the available installation space and the required steam output.
Steam boilers must undergo periodic inspection at least once a year with reference to the TS EN 12952, TS EN 12953 and TS 497 series of standards. High-temperature hot-water boilers are pressure equipment producing water at elevated temperatures. The reference standards include TS EN 12953-1, TS EN 12952-1, TS EN 12952-7, TS EN 12953-6 and TS 2025.
A high-temperature hot-water boiler heats pressurised water above its normal boiling temperature. The elevated pressure prevents it from vaporising, keeping it in the liquid phase. The entire system must remain continuously above a specified pressure to maintain the required water temperature. If the pressure falls below the saturation pressure corresponding to that temperature, the water immediately vaporises and creates a severe pressure surge in the system.
ID: 2301771147
A closed expansion vessel maintains the system pressure. Two types of expansion vessel are used:
– Nitrogen-cushioned expansion vessels with direct water contact
– Diaphragm expansion vessels
The expansion vessel accommodates thermal expansion while maintaining system pressure. Nitrogen is used as the cushioning gas because it is inert.
High-temperature hot-water boilers must undergo periodic inspection at least once a year with reference to the TS EN 12952, TS EN 12953 and TS 497 series of standards. Thermal oil systems resemble steam boiler systems but use oil instead of water, allowing much higher temperatures. Thermal oil boilers are used in industries requiring high temperatures, including asphalt plants, aluminium factories and plastics manufacturing facilities.
ID: 2172656805
Thermal oil boilers generally use an open system. However, the hot oil should not come into direct contact with the atmosphere, because contact with oxygen can cause a fire. A closed system must have a safety valve. This arrangement is used where the building is not high enough to place the expansion vessel at the required elevation. Safety-valve discharge pipes lead to the expansion vessel and then to the deaeration tank. If excess oil is discharged through the safety valve, oil overflowing from the expansion vessel cools before entering the oil reserve tank.
Thermal oil boilers must undergo periodic inspection at least once a year with reference to DIN 4754-1. A central heating boiler produces hot water and is generally used for space heating and the provision of clean hot water.
Central heating boilers are designed as open or closed systems. Closed systems have been the most commonly used type in recent years.
Central heating boilers are used in all types of centrally heated buildings. Where factors such as insufficient boiler-room space or the cost of employing a boiler operator are relevant, cascade systems consisting of wall-mounted condensing boilers are also used.
Central heating boilers must undergo periodic inspection at least once a year with reference to the TS EN 303 series, TS 497, TS 430, TS EN 14394+A1 and TS EN 12828+A1. Quality begins with confidence. Contact FQC Standard customer services to set your processes on a prompt and effective course. Contact