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A number of elements need to be considered when designing bespoke external lifts.
Water finds its way into every place that it isn't adequately sealed. The Sesame system is made from stainless steel 304 as standard, with many elements made from mild steel. The mild steel elements need to be accessible so they can be painted each year. All parts that rub against each other must either have a maintainable nylon cover or should be made from stainless steel if they require extra strength.
Sesame Access Systems have also installed external lifts by the sea. The salty air corrodes steel at an accelerated rate, meaning in salty environments Sesame move from Stainless Steel 304 to Stainless Steel 316, which has a far higher resistance to corrosion. We have also designed a lift to transport users over a change of levels in a swimming pool, for which Stainless Steel 314 was used throughout.
As you know, when water freezes it turns into ice. This means that the water that makes its way into all the nooks and crannies within an external lift freezes in temperatures below zero degrees, during which time it expands. This can cause some parts parts of the lift to be restricted in their movement. In the UK this is not a main concern, however in geological areas where extreme low temperatures are common this element must be designed out. For example heaters can be introduced into the lift system to help make the parts more resilient to extremely low temperatures.
On the other end of the thermometer heat can also be an issue. Overheating of mechanical parts must be considered at the design stage. Generally the specification of parts that work in the expected range of temperatures for the installation site is the answer.
The wind believe it or not must also be considered when designing external lifts. If you have a gate that will open into an external environment then the wind may trigger the pressure switches. The gate should either be designed out by using a Sesame rising barrier, the sensors should be changed from pressure to proximity, the gate could be made perforated whilst ensuring that fingers could not get through or trapped or the gate should be made manual rather than automatic.
Lightning could be a consideration in geographical areas that are known for their lightning storms. The external lift must be earthed as a rule of thumb, but in extreme circumstances lightning cables could be attached to the lift.
The external lift should always have sufficient light for the user and surrounding pedestrians to use the lift safely. The lifting carriage should be fitted with its own lighting system so users can see where they are going, with lights also in each of the buttons to help the user differentiate and the lift more easy to control.
Often the local authorities need to be informed of the installation of an external lift, due to planning permission being required in most cases. This is where the Sesame product range comes into their own. All of our external lifts are designed to blend into their environment, meaning we often find that English Heritage, Planning Officers and Access Consultants are recommending our product range. This is mostly the case when other products simply are not suitable. The architectural merit of a building must be maintained when conforming to the Disability Discrimination Act.
Electro Magnetic Emissions must be kept to a minimum when fabricating each external lift and internal lift for that matter. The machinery directive is a set of standards that is in place to police this statement. For instance, in one of our lifts located in an Apple store, if the system's hydraulic motor emitted electro magnetic signals that interfered with the hardware in an Apple store, such as an iPhone, then our lifts wouldn't be allowed in the building.
External lifts are often subject to a lot of vandalism. While it is not always possible to stop vandals from attacking an external lift, measures should be taken to reduce the appeal to vandals. If there are lots of parts that can easily be damaged then they will get damaged, so a good construction is a must. The sesame system, when at rest, looks like a standard set of stairs. This is a huge advantage when trying to stay inconspicuous to potential vandals. If they do not know that a wheelchair lift is there then they will not attack. Generally, external lifts should be switched off at night. If there is a button that can be pressed in the public view, it usually gets pressed.
Please take a moment to view our wheelchair access lifts web page