OS3 Specialised works categories

SOA category OS3

Water and sanitary systems, kitchens, laundries

OS3 covers water, sanitary, gas and fire-fighting systems, industrial kitchens and professional laundries: supply, installation, maintenance and renovation.

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The scope of OS3: water and sanitary systems in hospitals, fire hydrant networks in school buildings, industrial catering kitchens

SOA certification OS3: areas of application

OS3 brings water, gas and fire safety to every type of building. The main sectors:

Water and sanitary systems: hot and cold water networks, drains, sanitary fixtures and taps. They are found in every building.
Fire-fighting: hydrants, sprinklers, water mist systems, foam and extinguishers, pumps and reserve tanks. Mandatory in public buildings and in activities subject to Fire Brigade inspection.
Gas: methane and LPG networks inside buildings and connections for cookers, boilers and water heaters.
Industrial kitchens: complete kitchens for hospitals, schools, canteens and hotels, with cooking lines, hoods, dishwashers and cold rooms.
Professional laundries: industrial washing machines, ironers, dryers and water recovery systems for hospitals and hotels.
Water treatment: softeners, filters, reverse osmosis and disinfection systems.
Legionella prevention: hot water recirculation, disinfection and temperature control, essential in hospitals, care homes and hotels.
Remote control: remote monitoring of water consumption and fire-fighting networks.

In short: OS3 is the category of water safety in buildings.

UNI EN 12845 sprinkler fire-fighting system: reserve tank, pressurisation unit, false-ceiling network with automatically activated sprinklers

SOA categories related to OS3

OG11

Technological systems

groups together OS3, OS28 and OS30. Companies holding OG11 can carry out OS3 works in the same classification.

OS28

Heating and air-conditioning systems

deals with hot water production (boilers, heat pumps); OS3 with the network that distributes it. Together they cover the whole cycle.

OS30

Internal electrical systems

overlaps with OS3 in electrical fire-fighting systems and in the power supply to pumps, kitchens and laundries.

OG1

Civil and industrial buildings

is often the prevailing category in contracts where OS3 can be separated out, for example Community Houses.

OG2

Restoration and maintenance of protected real estate

works alongside OS3 in listed historic buildings that need to be upgraded with water and fire-fighting systems.

OG6

Water mains, gas pipelines, oil pipelines, irrigation and drainage works

brings water and gas up to the building; from there on, inside, OS3 takes over.

OS14

Waste disposal and recovery plants

deals with actual treatment plants; OS3 only with pre-treatment in the individual building.

OS22

Water treatment and purification plants

builds large water treatment plants; OS3 the small filtration systems inside buildings.

Industrial catering kitchen: extractor hood with filters, cooking line with hotplates/oven/bain-marie, professional dishwasher, gas/water/drain connections

Why it pays to qualify in OS3

OS3 has a very large market ahead of it, supported by four public investment streams:
· the Health for Community Houses, Community Hospitals and new hospital beds;
· the fire-safety upgrading of schools;
· the Safe and Sustainable Hospital programme;
· the maintenance of public buildings, with thousands of fire-safety certifications expiring every year.

SOA category OS3: frequently asked questions

Download PDF technical data sheets

What is the official description of category OS3?

OS3 “concerns the supply, installation and maintenance or renovation of water and sanitary systems, kitchens, laundries, gas and fire-fighting systems, whatever their degree of importance, complete with all related masonry, complementary or ancillary works, to be carried out in general works that have already been completed or are under construction”.

What are the main technical standards for fire-fighting?

UNI EN 12845 for sprinklers, UNI 10779 for hydrant networks and UNI/TS 11559 for dry hydrants, as well as Ministerial Decree of 20/12/2012 and Presidential Decree 151/2011.

What is the difference between OS3 and OG6?

The boundary is the meter. OG6 covers external networks (water mains, gas pipelines); OS3 everything inside the building.

Which works count as CEL for OS3?

Water and drainage networks, fire-fighting systems, industrial kitchens, laundries, gas networks and legionella prevention. The mere supply of sanitary fixtures or minor maintenance might not be recognised: it is best to ask the client for detailed CELs.

Your next move?

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