AOV windows, screens and steel doorsets, All Hallows, Bedford

30 to 34 All Hallows sits in the middle of Bedford and was refurbished to serve residential accommodation. The wider refurbishment was the main contractor's; we were the glazing and doors subcontractor within it. The package was eight white aluminium DualFrame 75Si automatic opening vent window units, a Technal STII glazed entrance door and screen, one large fixed Sheerline Prestige aluminium screen, ten steel doorsets and the specialist glazing that went with them.

The AOVs are the part a specifier will look at first. They form part of the building's smoke ventilation strategy, so the opening configuration and the free area each unit had to achieve were coordinated against the design rather than settled on site. One recorded unit achieves an approximate geometric free area of 1.52m². Glazing across the aluminium package is predominantly 28mm double glazed units, laminated and toughened, with a low-E softcoat and argon fill.

The fixed screen is 3010mm by 3030mm and is formed from nine fixed glazed fields. At that size the difficult part is not the specification, it is getting it into the building. Access was restricted, and the larger and heavier items had to be brought in through tight spaces and limited routes, so deliveries and installation sequencing were planned around that. It is the difference between a screen that arrives in one piece and one that arrives damaged.

The other technical requirement was the ten steel doorsets, which are fire rated and had to meet the project specification for that. We were appointed by the main contractor, who we have worked with on other projects. What makes this one worth writing up is the breadth of it: automated aluminium windows, a glazed entrance system, a large fixed screen and specialist steel doors are four different products with four different lead times, and coordinating them is a different job from installing one product a hundred times.