The peak bare surface temperature of 146 °C comes from the FLIR survey of a working Bosch UL-S package boiler. The 4.3 kW bare heat loss is calculated from surveyed temperatures and CAD-derived areas uplifted ×1.4 for bolts and irregular geometry. The area field opens on the value that reproduces that loss at that temperature, so the bare tile starts on the calculated reference; where a view holds elements at different temperatures this comes out below the geometric area. Surface heat loss only, ISO 12241 steady state. Emissivity 0.90 bare and 0.85 on the insulated face; fuel at 94 % heat-supply efficiency and 185 kg CO₂e per MWh of fuel. Operating hours and energy price are example inputs for one boiler — put your own in. Figures are for one boiler.
On the surveyed bosch ul-s package boiler the hottest point of this view measures 146 °C bare, and the 2 element group(s) in it lose 4.3 kW. The largest single item in it is the front (boiler) door at 2.5 kW.
With Inzonex Modular Insulation over the same area the calculated loss is 0.2 kW, which is 94.8 % lower. The calculated reduction rounds to 95 %. At 6,000 operating hours a year that is 24.5 MWh of heat retained.
Visible in this view: front (boiler) door (96 °C) and burner flange (146 °C) — bare.
| This view | Bare | Insulated |
|---|---|---|
| Surface heat loss | 4.3 kW | 0.2 kW |
| Surface temperature | 146 °C | 36.1 °C |
| Heat retained / yr | — | 24.5 MWh |
| Fuel equivalent / yr | — | 26.0 MWh |
q = h(Ts − Ta) + εσ[(Ts+273.15)⁴ − (Ta+273.15)⁴], with h = 5.7 + 3.8v W/m²K. Conductivity is taken as λ = 0.031 + 0.000188 × mean layer temperature, W/mK, evaluated at the solved mean layer temperature. Certified λ curves differ between products.
With a 50 mm core the calculated outer surface is 36.1 °C. The design target for surfaces people work next to is 45 °C. The bare steel measures 146 °C over the same area on the FLIR survey.
Inputs: 50 mm core, air 28 °C at 0.5 m/s, emissivity 0.90 bare and 0.85 on the insulated face, bare surface 146 °C. Area, temperature and hours are editable in the calculator above.
| Calculation input | Value |
|---|---|
| Insulation thickness | 50 mm |
| Ambient air | 28 °C |
| Air speed | 0.5 m/s |
| Emissivity, bare / insulated | 0.90 / 0.85 |
| Area uplift for bolts | ×1.4 |
The insulation is made in separate sections around the hinged doors, the valves and the mountings. Each section can be removed separately for burner service or inspection and refitted afterwards. Safety devices and required clearances stay unobstructed.
No access-time saving is included in this calculation.
| Stays accessible | How |
|---|---|
| Hinged doors | own section |
| Valves and mountings | own section |
| Instruments | own section |
| Safety devices | left clear |
Reference case: one boiler, this view at 146 °C bare, 6,000 operating hours a year. The retained heat is valued at £1,302 a year at £50/MWh of fuel and avoids 4.8 t CO₂e.
Natural gas at £50/MWh, 94 % heat-supply efficiency and 185 kg CO₂e per MWh of fuel. Operating hours and fuel price are example inputs for one boiler; enter your own to recalculate the results.
| Per year | Reference case |
|---|---|
| Estimated energy cost saving | £1,302 |
| Heat retained | 24.5 MWh |
| Fuel equivalent | 26.0 MWh |
| Emissions avoided | 4.8 t CO₂e |
Figures are for one boiler and for this view only. The surface is treated as flat area: thermal bridges and fixings are not resolved separately.
FLIR-measured at 96 °C bare over a 2.3 m² face; the burner flange beside it reached 146 °C.
Yes — a removable panel hinges with the door, insulated when closed and clear of the burner mounting and sight port when open.
The default 50 mm calculation gives 36.1 °C at 28 °C ambient and 0.5 m/s air speed. This is a modelled result, not the separate field-case measurement of 30 °C. The project target is 45 °C; contact safety also depends on surface material and contact duration.