A boiler inspection is an examination of the pressure system by a competent person, carried out to a written scheme of examination. In the United Kingdom the regime is the Pressure Systems Safety Regulations 2000. The scheme names the parts to be examined, the nature of the examination and the interval. Every part it names on a shell boiler is a part that has to be reached.
Boilers/This page
The written scheme is drawn up by a competent person and it is specific to the system. It names which parts are examined, how, and how often. Nothing about it is generic, and no interval quoted anywhere else applies to a particular boiler.
The user is responsible for having the scheme, for having the examinations done to it, and for keeping the records. The competent person is responsible for the scheme being suitable and for the examination being adequate.
Protective devices are named in the scheme in their own right. On a shell steam boiler that means the safety valve, the water level controls and the pressure limiter, and it is why those fittings are operated far more often than the shell they sit on.
We are not a competent person and we do not carry out examinations. What we did on the machines here is a thermal survey. Intervals, set pressures and the content of any particular scheme come from the documentation for that boiler.
| Examined | Why it is opened | What we measured on it |
|---|---|---|
| Manhole and inspection openings | Internal examination of the shell and the water side | 0.39 m² at 180 °C, 1,126 W |
| Safety valves | Lifted, tested, reset by a competent person | 0.68 m² at 180 °C, 1,963 W |
| Main stop and check valves | Travel and glands | 1.50 m² at 180 °C, 4,331 W |
| Front door and burner | Furnace and tube ends | 5.32 m² at 120 °C, 7,973 W |
| End plate and economiser | Gas-side cleaning and casing | 16.63 m² at 126–130 °C, 27,390 W |
| Blowdown valves | Operated on every blow | 0.52 m² at 180 °C, 1,501 W |
Every row is an opening. On the machines we surveyed every one of them was bare, and that is the pattern: fixed lagging is cut at the first examination and is not refitted afterwards, because refitting it means a lagger on site for one day of work.
The same items, priced at a range of fuel costs. 47.2 kW recovered, 7,700 hours, 90 per cent on the fuel.
| Fuel, €/MWh | Saved per year | Over ten years |
|---|---|---|
| 40 | €16,143 | €161,426 |
| 50 | €20,178 | €201,783 |
| 60 | €24,214 | €242,139 |
| 70 | €28,250 | €282,496 |
| 80 | €32,285 | €322,852 |
| 100 | €40,357 | €403,566 |
47.2 kW recovered on the machine we surveyed, 7,700 running hours, 90 per cent boiler efficiency on the fuel side: 363 MWh of heat and 404 MWh of fuel a year. Only the price changes down the column. The row at 60 €/MWh is the figure used everywhere else on this site, and the CO₂ that goes with it is 81.4 t a year at 201.6 kg/MWh.
The sequence below is the preparation the user carries out so the competent person can examine to the written scheme. The examination itself is their work, not the user’s and not ours.
Inzonex does not carry out examinations and is not a competent person. Intervals, the content of a scheme and set pressures come from the documentation of that boiler. What we did on these machines is a thermal survey.
An examination of the pressure system by a competent person, carried out to a written scheme of examination. In the UK the regime is the Pressure Systems Safety Regulations 2000.
A document drawn up by a competent person that names which parts of the system are examined, the nature of the examination and the interval. It is specific to that system.
A competent person, as defined under the regulations. The user is responsible for having the examinations carried out to the scheme and for keeping the records.
It depends on the scheme and on how much has to be opened. We do not carry out examinations and quote no duration.
Fixed lagging does, and that is why it is cut. Removable modules come off by hand at each opening and go back onto the same geometry afterwards.
On a shell steam boiler, the safety valve, the water level controls and the pressure limiter. They are examined in their own right and operated far more often than the shell.
The surveyed view this page came from, with every element on it.Open
→/ 02The fittings the scheme names, measured item by item at 180 °C.Open
→/ 03The protective device the scheme names first, and how it is tested.Open
→/ 04What the bare items in the table above are worth as a loss term.Open
→| Survey | FLIR S62 Pro, emissivity 0.90, reflected 25 °C, 3 m, full radiometric correction. UK commercial boiler house. |
| Geometry | Rebuilt in CAD from the surveyed machine. Area allowances are stated on the page they are used on and are allowances, not measured areas. |
| Calculation | ISO 12241 steady state. Heat loss is calculated from the measured surface temperature and the modelled area — it is not metered. Full method, basis and limits. |
| Regulation | The Pressure Systems Safety Regulations 2000 · HSE L122, Safety of pressure systems · HSE INDG261, Pressure systems |
Where surface loss sits inside the indirect method, and what 49.8 kW is against the fuel input.Open
→/ 02Which machine this is, and why the losing surfaces differ between the two.Open
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