Bremont HQ was designed by award winning architects Spratley & Partners and boasts strong eco credentials – including a substantial green roof and recycled air heating system. The building serves as an end-to-end mechanical watch manufacturing centre as well as containing a boutique store and substantial entertaining space. As Bremont HQ is the home of British watchmaking and has a fantastic reputation, it serves as a destination for watch lovers to visit from all over the world, with guided tours of the building being conducted regularly.
The Irrigation Project
Access Irrigation were responsible for the design and supply of the complete irrigation system watering the substantially sized, extensive green roof. This was a sedum roof and was 1130m². The system was fully automated, using a Heron Ma-6 irrigation controller. This controller has a large digital display for easy, accurate programming and a very high level of reliability, including featuring a permanent memory so programmes are never lost due to power failures. The controller features a pump freeze facility, which in conjunction with a float switch will suspend the programme in the event of a failure in the water supply. To prevent operation in wet weather a rain sensor was included. The controller was also supplied with sophisticated software which allows a long delay between irrigation cycles. This delay option is ideal for extensive green roofs like this one, which are drought tolerant and only require irrigation during dry spells. A Cat 5 pump & tank unit with a Type AB air gap was used to create a pressurised water supply and to comply with the Water Regulations regarding backflow prevention. Hunter PGV Jar Top solenoid valves were used to split the system into separate zones, allowing each zone to operate at a separate time, thereby providing good water flow and therefore efficient watering for each zone. The valves were fitted with adjustable pressure regulators, to ensure the correct operating pressure at the dripline. The solenoid valves were connected to the controller via signal cable and connected to the pump & tank unit via supply pipe.
Each solenoid valve is opened and closed in sequence by the controller. When the first valve opens, the pump will detect a drop in pressure (due to pressure release from the open valve) and will begin to operate to boost the pressure back up again. This will cause water to flow through the first (now open) solenoid valve to water the first zone. The controller closes the first valve, and immediately opens the next valve in the sequence. Once the last valve has closed, the water flow will cease, and pressure will build again, and the pump will stop operating.
For ease of installation, the controller and solenoid valves were mounted on a black metal plate supplied with pre-drilled fixing holes, allowing it to be conveniently wall-mounted. This control plate was supplied with connection to the mains power supply and was secured in a plant room, along with the pump & tank unit. The supply pipework from the pump & tank unit to the roof surface was supplied by our client.
The irrigation system watering the green roof was split into a total of 6 separate zones, the roof being watered using Permadrip-Pro dripline. Permadrip-Pro is a brown coloured dripline designed for landscape irrigation with a 16mm pipe diameter and a wall thickness of 1.2mm. The 1.6 L/h drip emitters are pressure compensating, ensuring uniform output over a wide pressure range and include a built-in anti-siphon mechanism, to prevent dirt being sucked into the drippers at the end of the irrigation cycle. These features make it ideal for use on sloping sites – such as this green roof. The emitters also have a large inlet filter and unique, continually self-cleaning design, giving excellent resistance to blockages. For the green roof, dripline of 0.15m dripper spacing was used, being laid out in lengths spaced every 3m apart for the majority of the roof, apart from the dripline runs at the centre of the green roof, which were spaced 1m apart at the very centre (3 runs) and 2m apart further out (2 runs). This was to ensure that the roof was watered evenly, with the middle of the roof being flatter, so requiring dripline runs closer together, and most of the rest of the roof sloping so requiring dripline runs spaced further apart. 25 runs of dripline were used in total – 4 runs for each zone, apart from zone 3 which used 5 runs. 20mm header pipe was used to run along the length of the roof, with Pozilock compression tee fittings used to connect to each of the 25 runs of dripline. Foldover stopends were used to terminate the header pipe runs and dripline runs at the end of each run. The dripline was secured to the sedum blanket covering the roof using nylon cable ties, to ensure that the dripline remained firmly in position to provide completely even watering.
Our project has resulted in a building that completely blends into its natural surroundings, with the substantial green roof attracting insects and birds and thus enhancing biodiversity. We are delighted with the result and are proud to play our part in helping a reputable company like Bremont to develop, whilst simultaneously having a positive impact on the natural environment.
Images courtesy of Bremont Watches. If you wish, you can take a tour of the stunning Bremont HQ