Hydrant Block Plans: What They Show, Where They Go and When You Need One
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A hydrant block plan is the site map mounted at your fire hydrant booster assembly so an arriving fire crew can work out, in seconds, where the hydrants are, where the isolation valves sit and how water moves around the building. If a fire brigade officer or your fire safety assessor has told you the block plan is missing, faded, or no longer matches the site, you need a new one drawn and installed before your next Annual Fire Safety Statement is signed off.
What a block plan actually is
When a pumper arrives at a building, the crew connects to the booster assembly out the front. From that point they are working blind unless something tells them what is behind the wall. The block plan is that something. It is a simple plan view of the site, mounted at or adjacent to the booster, showing the hydrant system laid out over the building footprint.
It is a firefighting tool, not an occupant tool. Nobody evacuating the building will ever look at it. That distinction matters because the two documents get confused constantly, and ordering the wrong one wastes a few weeks.
What has to be on it
AS 2419.1, the Australian Standard for fire hydrant installations, sets out what the block plan has to carry. The detail varies with the system, but on almost every site you are looking at:
- The building outline and site boundaries, drawn to a recognisable scale
- Location of the booster assembly itself, marked as the reference point
- All fire hydrants, internal and external, with hydrant landing valves identified
- Main isolating valves and their locations
- Fire hydrant pumpset location, if there is one
- Tank location and capacity where the supply is from a stored water tank
- Pipe runs and sizes for the hydrant mains
- A north point
- Street names and the main access points to the site
- Levels or floors served, on multi-storey buildings
The plan has to be oriented the way the person reading it is standing. A crew facing the booster should be able to look at the plan and have the building in front of them match the page. A north-up plan that puts the rear of the building at the top is technically accurate and practically useless.
It also has to be durable and readable outdoors for years. That usually means a printed plan behind glass or polycarbonate in a metal frame, or a printed metal or laminate panel, fixed at the booster where it will not be blocked by a gate, a bin or a parked car.
Block plan, evacuation diagram or booster plan?
| Document | Who reads it | Where it goes | Driven by |
|---|---|---|---|
| Hydrant block plan | Attending fire brigade | At or beside the hydrant booster assembly | AS 2419.1 |
| Sprinkler block plan | Attending fire brigade | At the sprinkler valve room or booster | AS 2118.1 |
| Emergency evacuation diagram | Building occupants | Corridors, lift lobbies, near exits | AS 3745 |
| Emergency procedure flip chart | Wardens and staff | At the warden point or reception | AS 3745 / AS 4083 for health care |
If you have both hydrant and sprinkler systems, you generally need both block plans. They are sometimes combined on one panel where the systems and the site are simple enough to show clearly, but on a large or staged site they are usually kept separate so neither gets cluttered. If what you actually need is the occupant-facing set, that is emergency evacuation diagrams rather than a block plan.
Who needs one
Any building with a fire hydrant booster assembly needs a block plan at that booster. In practice that covers most class 2 to class 9 buildings of any size: apartment buildings, offices, warehouses, shopping centres, schools, aged care, industrial sites and mixed-use developments.
In NSW, hydrant systems are almost always listed as an essential fire safety measure on the fire safety schedule. That means the system, including its signage and plans, has to be inspected and assessed each year by a competent fire safety practitioner before the Annual Fire Safety Statement can be issued to Council and Fire and Rescue NSW. A missing or wrong block plan is one of the easier things for an assessor to pick up, and one of the easier things to fix, but it will hold the statement until it is done.
When an existing plan needs replacing
You do not need a new plan every year. You do need one when:
- The site has changed. New building, new wing, a hydrant relocated, a carpark reconfigured, a boundary moved.
- The hydrant system has been extended or upgraded, or a pumpset or tank has been added.
- The plan has faded, the frame has filled with water, or the print has gone yellow and unreadable.
- The booster has been relocated, which changes the orientation the plan has to be drawn in.
- A brigade inspection or fire safety assessment has flagged it as non-compliant.
A block plan that no longer matches the building is worse than none at all, because a crew will act on it.
How one gets produced
There is no way to draw an accurate block plan from a desk. The process runs roughly like this:
- Site attendance. Someone walks the site and records every hydrant, valve, pump, tank and booster, with measurements and photos.
- Existing documentation. Hydraulic drawings, as-built plans and the fire safety schedule are pulled together where they exist. Pipe sizes in particular usually come from the hydraulic set.
- Reconciling the two. On older buildings the drawings and the site rarely agree. What is physically there wins.
- Drafting. The plan is drawn to scale, oriented to the booster viewpoint, with the standard symbols and legend.
- Proofing. You check it before it is printed. This is the point to catch a wrong street name or a missed hydrant.
- Production and installation. Printed on durable stock, framed, and fixed at the booster.
Turnaround depends on how big and how complicated the site is, how quickly site access can be arranged, and whether usable hydraulic drawings exist. A single-building site with good drawings is quick. A staged industrial estate with three boosters and no paperwork is not.
If you want to see what goes into a drawn set for your building, start with the block plans service and the block plan information page.
FAQ
Can I just print the architect's site plan and frame it?
No. An architectural site plan shows a building. A block plan shows a fire hydrant system over a building, with the valves, mains, sizes, pumps, tanks and legend a crew needs, oriented to the booster. The base drawing can be a useful starting point for the drafter, but on its own it will not pass an assessment.
Does the block plan have to be inside a locked cabinet?
It needs to be protected from weather and vandalism and readable at the booster without a key. Many sites mount it in a sealed frame on an external wall or on the booster cage itself. A plan locked inside a cabinet that only the building manager can open defeats the purpose.
We have hydrants but no booster. Do we still need a block plan?
Smaller systems without a booster assembly can still benefit from a plan at the main isolating valve or brigade entry point, and your fire safety schedule may call for one. Have your fire safety practitioner confirm against the schedule and the standard your system was designed to, rather than assuming either way.