Water Tube Boiler Water Treated Reference Standard
Water Tube Boiler Water Treated Reference Standard
Water Tube Boiler Water Treated Reference Standard
1. Scope
This part of this European Standard applies to all shell boilers as defined in EN
12952-12 which are heated by combustion of one or more fuels or by hot gases for the
generation of steam and/or hot water
2. Standard reference
Corrosion risks
Sludge elimination
Formation of deposits
For the purpose of this part of this European Standard, the terms and definitions
given in EN 12952 and the following definitions apply:
3.3. Make up water : Water which compensates for losses of water and
steam from the system
4. Requirements
EN 12952-12 Table 5-1 - Feedwater for steam boilers and hot water boilers with natural and forced circulation
Operating pressure Barg > 0.5 to 20 > 20 to 40 > 40 to 100 total range total range
EN 12952-12 Table 5-2 - Boiler water for steam boilers and hot water boilers
Operating pressure Barg > 0.5 to 20 > 20 to 40 > 40 to 60 > 0.5 to 60 > 60 to 100 ≤ 100 > 100 total range total range
Appearance ─ clear, no stable foam
pH value at 25°C b ─ 10.5 to 12.0 10.5 to 11.8 10.3 to 11.5 10.0 to 11.0 9.8 to 10.5 9.5 to 10.5 9.3 to 9.7 > 8.0 d 9.0 to 11.5 e
Alkalinity mmol/l 1 to 15 b 1 to 10 b 0.5 to 5 b 0.1 to 1.0 0.1 to 0.3 0.05 to 0.3 ─ ─ <5
Silica (SiO2) concentration mg/l pressure dependent, see Figure 5.3 or 5.4 ─
Phosphate (PO4) concentration mg/l 10 to 20 8 to 15 8 to 15 5 to 10 <6 <6 <3 ─ ─
Organic substance concentration mg/l see footnote h
f If coordinated phosphate treatment is used, considering all other values higher PO4-concentrations are acceptabic (see also clause 4).
g See table 5.1
Note
The oxygen in the feed water must be reduced primarily using physical
processes, e.g. thermal pressure deaeration, to the described limit values. Because in
practical operation, partly through frequent down times, start up and run down processes
etc. and with partial deaeration systems, compliance with the limit value is not guaranteed
using deaeration alone, an oxygen binder should be added. Non-volatile sodium sulphite,
for example, has proved effective-there are no hygienic / toxicological restructions Addition
to the feed water should be carried out in such a way that the limit values for the boiler
water are maintained. The need for this and the choice of a suitable dosing agent must be
decided in each individual case.
locked, i.e. the conductivity to regulated is to be set with a sufficient distance from the limit
value . If unusually pure steam is needed, it may be under some circumstances that the
maximum conductivity values in the boiler water need to be lowered for this special case.
The feedwater, boilerwater and Attemperator spray water in steam boilers and
the boiler water in hot water boilers shall be checked for the relevant parameters such as
pH, direct conductivity, acid conductivity, hardness and oxygen of oxygen scavenger.
The sampling of water and steam from the boiler system shall be performed in
accordance with ISO 5667-1 and the preparation and handing of samples in accordance
with ISO 5667-3.
Sampling points: