Crucially, with self-harm and suicide an ever-present risk, the window had to be free of any features which could be used to attach a ligature. This automatically ruled out a casement or vertical sliding sash design, and we quickly decided on a horizontal sliding sash window.
Projecting handles, locks, hinges or vents were also ruled out. But it didn’t stop there. Input from the trust’s clinical experts revealed that the most determined patients will employ an astonishing degree of ingenuity and will find and exploit any weaknesses in a design to achieve their goals.
Our search for the optimum design began with an existing horizontal sash window which is popular and widely used on the continent, though less well known in the UK. This was coupled with experience and the use of components more normally associated with security screens as you would find in high street banks.
To test various design features, approved specialist contractor Polar (NE), who worked with us to develop the design, produced prototype fabrications and built a special test rig.
“Design development was almost a process of trial and error. The trust would identify a problem and the design team would then try to design it out,” said Polar managing director John Wilson.
This was unfamiliar territory for all of us. There are no test standards or window testing procedures in the NHS generally, all our tests had to be devised and agreed as the design developed.
“I don’t think any of us realised how complex this was going to be when we first started,” said Mr Wilson.
With the prototype installed in the test rig, various attempts were made to damage or destroy it. Workers from the Polar assembly line kindly volunteered to carry out the tests while the trust provided its own volunteers, one of whom was an experienced senior ward manager.
“We were able to dismantle the restriction device of the opening sash of the first mock-up using ordinary canteen cutlery. I think the product people got a bit of a shock when they realised how relatively easily it could be done. We must have tested at least four prototypes before we were satisfied that the design met the specification,” said John Ord.
The client’s clinical personnel, whose day-to-day contact with patients has exposed them to the full gamut of disruptive behavioural activity, were crucial in identifying weaknesses in the design which we would not have recognised.