Feb 162015
 

Design Considerations for an Oxygen Cylinder Holder for Wheelchairs & Mobility Scooters (Bristol Remap case reference 11\14-07)

Design Considerations

The table below summarise some design considerations for the oxygen cylinder holder:

Information Design Consideration
Oxygen cylinders are safety critical to the user The holder material must be strong enough to securely hold the cylinder. The attachment of the cylinder to the chair must have no chance of failure. Multiple straps/ties would bring redundancy but because failure from fatigue is most likely to occur at a tie or buckle, a 1 piece design would be best. Additionally, tubing to oxygen face masks and nasal cannula must be clear of moving parts.
There is no standard oxygen cylinder dimensions – cylinder length varies with the nozzle type A ‘one size fits all’ solution may not be possible. A cylinder holder made of an elasticated material would be adaptable to a variety of cylinder sizes, but material elasticity may result in an unacceptable compromise on material strength.
Oxygen cylinders must be stored upright The cylinder should not be stored horizontally alongside or under the seat.
Users should not be encumbered by the cylinder The cylinder could be stored behind the seat where it is less likely to be in the user’s way. However, some individuals may already use this space for storage. One possibility is storing the holder on one side of the back of the chair leaving space for storage, but this leads to balance/attachment issues.
Oxygen cylinders must be stored away from heat sources Cylinder should be insulated from or stored away from mobility scooter motors which can become hot. The motors are usually found at the bottom of the back of the scooter, but most are already well shielded.
Oxygen cylinders must be easily accessible in case urgent assistance is needed Cylinder should not be stored in a location difficult to reach by others e.g. under the seat ; additionally the cylinder should not be covered by something that is difficult to remove
Oxygen cylinders should be stored in clean, dry and well-ventilated conditions The holder material must be cleanable. It must not cover the entire oxygen cylinder.
Users should be able to use oxygen cylinders in all weather conditions The cylinder holder material must endure all weather conditions. Canvas is durable, cheap and easy to manufacture into custom shapes. A metal frame for the oxygen tank would be very strong and durable to weather (assuming it’s not copper), however metal frames require permanent attachment which cannot be easily removed.
Wheelchairs & mobility scooters are often under vibrational loads Any attachments for the holder must be resistant to becoming loose or untied under vibrational loads. Multiple attachment points would be better but a 1 piece design with no ties would be best. The holder must not slip off the chair under vibrational loads.

UK Oxygen Cylinder Regulations

General[1]

Oxygen is classified as a general sales list medicine. As such, it may be purchased without a prescription. There are currently several companies in England contracted to provide Home Oxygen Services for the NHS, each covering a specific geographical area:

· BOC

· Air Liquide

· Air Product

· Dolby Vivisol

· Oxygen Store

Oxygen Store appears to be the most popular for the Bristol area.

Home Storage Advice

Following is home storage advice for oxygen cylinders from the NHS. Some is applicable to personally transported oxygen cylinders:

· Keep your portable oxygen cylinder away from sources of heat, such as a radiator, fire or naked flame e.g. a candle

· Do not smoke in the same room as your portable oxygen cylinder

· Store the portable oxygen cylinder in a clean, dry and well-ventilated room. Do not store in a cupboard

· The cylinder must be easily accessible to the nursing staff visiting your home.

· You must not let any other people use this oxygen cylinder.

· If the emergency services attend your home, please remember to tell them that there is an oxygen cylinder within the home and where it can be found.

· If you do not want the portable oxygen cylinder to remain in your home, please inform the visiting nursing staff

Oxygen Tank Sizes

The internal volumes for oxygen cylinders tend to be relatively standard throughout the companies (1L – 5L) but the relative dimensions vary. For example, in the case of a 2L cylinder, dimensions vary from 470×100 to 530×100 mm depending on the nozzle type alone[3].

It was found that the cylinder length can vary a lot but the diameters for both 1L and 2L cylinders would vary between 85mm and 125mm.

There are also oxygen concentrators which are a more expensive option – these are a completely different shape so would need a different shaped holder design.


[1] Q&A 335.2 – NHS, UK Medicines Information, 12th April 2013

[3] Medical Gas Cylinder Data Chart, Air Liquide

 

Existing Solutions

 

Note: Certain customers may be VAT exempt and so the purchase price may be 17.5% less than the prices stated below

Vinyl Value Ltd.

E-mail: enquiries@vinylvalue.co.uk

Tel: 01297 560651

Fax: 01297 560086

Cost: £23.00 (Via mobilitypitstop.com)

Observations

· Canvas is strong and durable to all weather conditions

· Cylinder is easily accessible and not covered

· Cylinder is out of the way of the user but limits other storage

· Holder appears to be a 1 piece design so no risk of ties loosening, however there is a risk of slipping off the chair in the absence of a head rest

· In contrast if there are ties on the straps this design could fit on a wider range of mobility scooters

Mobility & Bathroom Solutions

Website: www.mobilitybathroomsolutions.co.uk

Tel: 01489 584443

Cost: £42.00

Observations

· A metal frame is durable to all weather conditions

· The cylinder is easily accessible but not easily removed due to

the tightening screws

· Frame is easy to clean but not easy to remove

· There is gap keeping the cylinder clear of the warm motor and allowing

the space behind the chair to be used for other storage needs

· Metal may be less damped against vibrations than other materials

RDK Mobility

Website: www.rdkmobility.co.uk

Tel: 0800 1075118 or 0800 1075122

Cost: £37.94

Observations

· Multiple straps make this design very stable

· If the straps are a single piece of elastic material, then the absence of

ties or buckles mitigate the risk of them becoming untied under vibrational

loads whilst maintaining the ability to fit the design to a wide range of scooters

· However, there may be a chance that the top strap could slip of the

shoulder of the chair under these loads

It’s simplicity means the cylinder is very easy to access and remove in emergencies

Active Mobility Centre

E-mail: enq@activemobility.co.uk

Tel: 01642 805050

Cost: £20.00

Observations

· A single attachment point means that this design may be susceptible to swinging

· Attachment isn’t possible without a head rest

· The oxygen tank is fully covered

· Canvas is a strong and durable material

REMAP Bristol case 4\14-01

Observations

· Wooden mounting is strong, durable and easy to clean

· Straps are very secure but may make it difficult to remove the cylinder in an emergency

image Vinyl Value Ltd

image Mobility & Bathroom Solutions

image RDK Mobility

image Active Mobility Centre

image Remap Bristol solution case ref 4\14-01

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Document written December 2014

 February 16, 2015  Posted by at 11:23 Technical Articles