The sprinkler head itself is manufactured to EN 12259-1, but four small items that determine the head's working life on site are regulated directly in Clause 14 of TS EN 12845+A2:2026: the guard, the water shield, the escutcheon (rosette) and corrosion protection. Together these four subclauses occupy half a page, yet they are among the items most often missed in site inspections. Every provision below is drawn from the standard's own wording. Source: TS EN 12845+A2:2026, Clauses 14.6-14.9, EN p.106-107 (TSE p.109-110).
1. Clause 14.6: Sprinkler guards
The clause is a single sentence:
Sprinklers, other than ceiling or flush sprinklers, shall be fitted with a suitable metal guard where they are installed in a position subject to a risk of accidental mechanical damage. Clause 14.6 (EN p.106)
Three binding elements follow from that sentence:
- Types outside the scope: ceiling and flush sprinklers. The heat sensitive element of these types is already recessed into the plane of the ceiling (Clause 3.55, EN p.20).
- Triggering condition: a "position subject to a risk of accidental mechanical damage". The standard does not quantify this risk; it gives no threshold in terms of height, forklift traffic or proximity to a doorway. The decision rests with the designer and the authority.
- Material: metal. Clause 14.6 offers no alternative permitting a plastic or composite guard.
Field note: the guard itself forms an obstruction to the water distribution of the sprinkler. Since the standard gives no obstruction criterion for guard geometry under Clause 14.6, the selection is left to the supplier's list of guards approved with the head.
2. Clause 14.7: Water shields
A water shield prevents water from a sprinkler above cooling the heat sensing element of the sprinkler below and delaying it (cold soldering). The rule of the standard has two parts:
| Subject | Provision | Source |
|---|---|---|
| Where required | On sprinklers mounted on racks, or mounted under perforated shelves, platforms, floors or similar positions, where water from the sprinkler(s) above could wet the vicinity of the bulb or fusible element | Clause 14.7, EN p.106 |
| Minimum diameter | 0.075 m (metal shield) | Clause 14.7, EN p.106 |
| Attachment on uprights | Not to be attached directly to the deflector or the yoke | Clause 14.7, EN p.106 |
| Bracket design | Such that obstruction to the sprinkler water distribution is minimised | Clause 14.7, EN p.106 |
In practice the most common location for water shields is in-rack sprinklers. Clause 12.5.1 (EN p.78) requires in-rack sprinklers to be installed in the longitudinal flue space of double row racks, preferably at the intersection with a transverse flue; in that position the water from the upper level falls directly onto the sprinklers at the level below. The shield is the mandatory complement of that geometry.
3. Clause 14.8: Escutcheons
An escutcheon is the ring that closes the gap between the sprinkler and the ceiling opening. The standard sets three constraints:
- Material: metal or thermoset plastic. A thermoplastic escutcheon is not among the materials the standard permits.
- No supporting function: "Escutcheons shall not be used to support ceilings or other structures."
- Projection limit: "No part of an escutcheon shall project below the ceiling lower than the top of the visible part of the heat sensitive element of the sprinkler."
The third rule prevents the escutcheon from screening the heat flow. Clause 14.5.2 (EN p.106) turns the same logic into a general rule: "the thermal response of sprinkler systems shall not be impeded", and since sprinklers other than those in racks normally operate through the horizontal flow of hot combustion gases, "nothing shall interfere with this horizontal flow".
4. Clause 14.9: Corrosion protection
Clause 14.9 (EN p.107) consists of two sentences:
Sprinklers installed in locations where corrosive vapours prevail shall be protected by a suitable corrosion resistant coating applied by the supplier in accordance with EN 12259-1, unless the sprinkler is manufactured from suitable corrosion resistant materials. No corrosion inhibiting treatment shall be applied to sprinkler bulbs.
The critical words here are by the supplier. Clause 14.1 (EN p.103) completes the picture: only new (unused) sprinklers shall be used, they shall not be painted except as permitted by EN 12259-1, and no decoration or coating shall be applied after despatch from the manufacturing factory, the sole exception being Clause 14.9. In other words, a "corrosion paint" brushed on at site is contrary to the standard.
A second constraint related to corrosive environments concerns type selection. Clause 14.2.2 (EN p.104) prohibits the use of sprinklers without a fixed deflector (for example types with a retracted deflector that drops into the operating position when the sprinkler operates) in the following situations:
- where ceilings slope more than 45° from the horizontal;
- where the atmosphere is corrosive or is likely to have a high dust content;
- in or under racks.
5. Corrosion provisions elsewhere in the system
The corrosion provisions outside the sprinkler head are in Clause 17 and Clause 20:
| Subject | Provision | Source |
|---|---|---|
| Painting | Ungalvanized ferrous pipe is painted where environmental conditions require it; galvanized pipe is painted wherever the coating has been damaged (for example by thread cutting) | Clause 17.1.7, EN p.112 |
| Copper to steel joint | Flanged with stainless steel bolts; no bending on site; precautions taken against galvanic corrosion | Clause 17.1.9, EN p.113 |
| Copper pipe hanger | Suitable lining of adequate electrical resistance to prevent contact corrosion | Clause 17.2.1, EN p.113 |
| Quarterly routine | Pipework and hangers are checked for corrosion and painted where necessary; bitumen based paint is renewed | Clause 20.3.2.4, EN p.120 |
| Quarterly routine (heads) | Sprinklers contaminated with deposits other than paint are carefully cleaned; painted or distorted heads are replaced | Clause 20.3.2.3, EN p.120 |
| Petroleum jelly coating | Existing petroleum jelly coatings are checked and, if necessary, removed and two fresh coats applied (on glass bulb sprinklers only to the body and yoke) | Clause 20.3.2.3, EN p.120 |
| Storage and pressure tanks | Internal inspection every 3 years, emptying and cleaning if necessary, corrosion inspection and repainting or renewal of the protection | Clause 20.3.5.2, EN p.122 |
| Pressure tank | Protected against internal and external corrosion | Clause 9.5.1, EN p.54 |
The NOTE to Clause 17.1.7 is short but important: "Additional protection may be required for unusually corrosive conditions." The standard does not state what that additional protection should be.
The provision in Clause 20.3.2.3 that a paint contaminated head is replaced and the coating permission in Clause 14.9 complement each other: a factory coating is legitimate, while site paint is a defect requiring the head to be replaced.
6. Stock of replacement sprinklers
The stock to be fitted in place of a damaged or operated head is regulated in Clause 20.1.4 (EN p.118):
- Replacement sprinklers, together with the sprinkler spanners supplied by the supplier, are kept in a cabinet or cabinets in a conspicuous and readily accessible position; the ambient temperature shall not exceed 27 °C.
- Minimum number of spares per system: 6 for LH, 24 for OH, 36 for HHP and HHS.
- The stock is replenished without delay after use.
- Where the installation includes high temperature sprinklers, sidewall or other pattern variations, or multiple controls, a sufficient number of these is also held in stock.
In a facility using heads with a corrosion resistant coating this last item applies directly: the spare stock must carry the same coating, because applying the coating on site is not possible under Clauses 14.1 and 14.9.
Frequently Asked Questions
When is a sprinkler guard mandatory?
TS EN 12845+A2:2026 Clause 14.6 (EN p.106): sprinklers other than ceiling and flush sprinklers shall be fitted with a suitable metal guard where they are installed in a position subject to a risk of accidental mechanical damage. For the guard the standard specifies metal only; there is no provision allowing a plastic guard.
What is the minimum diameter of a water shield?
Clause 14.7 (EN p.106) requires a metal water shield of at least 0.075 m diameter. The shield is fitted to sprinklers mounted on racks, or mounted under perforated shelves, platforms, floors or similar positions, where water from a sprinkler above could wet the bulb or fusible element.
How is a water shield attached on an upright sprinkler?
Clause 14.7 (EN p.106): water shields on upright sprinklers shall not be attached directly to the deflector or to the yoke. Any bracket supports used shall be designed to minimise obstruction to the water distribution of the sprinkler.
What material may an escutcheon be, and how far may it project?
Clause 14.8 (EN p.107): escutcheons shall be made of metal or thermoset plastic. Escutcheons shall not be used to support ceilings or other structures. No part of an escutcheon shall project below the ceiling lower than the top of the visible part of the heat sensitive element of the sprinkler.
Can we paint sprinklers on site in a corrosive environment?
No. Clause 14.1 (EN p.103) prohibits any decoration or coating being applied to sprinklers after despatch from the factory, except as provided in Clause 14.9. Clause 14.9 (EN p.107) requires the corrosion resistant coating to be applied by the supplier and in accordance with EN 12259-1; in addition, no corrosion inhibiting treatment shall be applied to sprinkler bulbs.
What does the standard say about galvanic corrosion with copper pipe?
Clause 17.1.9 (EN p.113): copper to steel joints shall be flanged with stainless steel bolts, the pipe shall not be bent on site and precautions shall be taken to avoid galvanic corrosion. Clause 17.2.1 (EN p.113) further requires hangers for copper pipe to be fitted with a suitable lining of adequate electrical resistance to prevent contact corrosion.
References
- TS EN 12845+A2:2026 Clause 3.55 definition of sprinkler, ceiling or flush (EN p.20 / TSE p.23)
- TS EN 12845+A2:2026 Clause 12.5.1 Position of in-rack sprinklers (EN p.78 / TSE p.81)
- TS EN 12845+A2:2026 Clause 14.1 General - prohibition of painting and coating (EN p.103 / TSE p.106)
- TS EN 12845+A2:2026 Clause 14.2.2 Ceiling, flush, recessed and concealed pattern (EN p.104 / TSE p.107)
- TS EN 12845+A2:2026 Clause 14.5.2 Interaction with other measures (EN p.106 / TSE p.109)
- TS EN 12845+A2:2026 Clause 14.6 Sprinkler guards (EN p.106 / TSE p.109)
- TS EN 12845+A2:2026 Clause 14.7 Sprinkler water shields (EN p.106 / TSE p.109)
- TS EN 12845+A2:2026 Clause 14.8 Sprinkler rosettes (EN p.107 / TSE p.110)
- TS EN 12845+A2:2026 Clause 14.9 Corrosion protection of sprinklers (EN p.107 / TSE p.110)
- TS EN 12845+A2:2026 Clause 17.1.7 Painting (EN p.112 / TSE p.115)
- TS EN 12845+A2:2026 Clause 17.1.9 Copper pipe (EN p.113 / TSE p.116)
- TS EN 12845+A2:2026 Clause 17.2.1 Pipe supports - General (EN p.113 / TSE p.116)
- TS EN 12845+A2:2026 Clause 9.5.1 Pressure tanks - General (EN p.54 / TSE p.57)
- TS EN 12845+A2:2026 Clause 20.1.4 Replacement sprinklers (EN p.118-119 / TSE p.121-122)
- TS EN 12845+A2:2026 Clause 20.3.2.3 Sprinklers, multiple controls and sprayers (EN p.120 / TSE p.123)
- TS EN 12845+A2:2026 Clause 20.3.2.4 Pipework and pipe supports (EN p.120 / TSE p.123)
- TS EN 12845+A2:2026 Clause 20.3.5.2 Storage and pressure tanks (EN p.122 / TSE p.125)
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Download MEP Calc on the App StoreTS EN 12845+A2:2026 (EN 12845:2015+A2:2026) Fixed firefighting systems — Automatic sprinkler systems — Design, installation and maintenance; TS EN 12845-2:2025 (EN 12845-2:2024) ESFR and CMSA sprinkler systems. Every figure in this article is taken from the published standard text; clause, table and page references are listed under References. General information only, not a substitute for the standard or for a design review.