Team:Macquarie Australia/Integrated Human Practices
INTEGRATED HUMAN PRACTICE
Following our interviews, we have designed prototypes for each stakeholder, implementing their industry specific advice. Our initial applications for the prototype was thought to be industrial monitoring of hydrogen concentration to detect leaks. Differences in hydrogen concentrations along a pipeline will indicate a hydrogen gas leak.
Our detector will inherently be specific, accurate and have good longevity, as outlined in our project description page.
We quickly realised the impracticality of this design, and we realised the biosensor would be more useful near a pipe rather than inside a pipeline.
NSW Fire + Rescue
The main feedback we received from NSW fire and rescue was simplicity. For this reason, a small, handheld device was preferred, and portability is essential.
What did we learn for our prototype?
- Reasonably fast detection (within 30 seconds)
- Specificity: No cross sensitivity with CO, NH3, hydrocarbons, H2S which is a limitation of current detectors
- Detect hydrogen gas when it reaches 40,000 ppm (the concentration at which it is considered a safety hazard)
- A detector that can be implemented in homes and industry
- End user accessibility: Firefighters often don’t use current detectors due to their overly complex nature. Paul, A scientific officer from Fire + Rescue NSW, encouraged the idea of having a coloured signal or output for easy usage and interpretation.
- Increased detector longevity: Current detectors only last approximately 16 hours and require monthly battery changes
How did we integrate the feedback?
- Portable design
- A simplistic legend is incorporated into the device itself to make readings clear and ensure no confusion. A positive reading would occur when hydrogen gas is present in the air at 40,000 ppm.
- A positive reading will be green, and is indicated by the word “danger” on the device. A negative reading is indicated by the word “safe” on the device.
- A transparent plastic window will be placed over the E.coli sample to ensure no bacteria will escape.
Maximator Pty Ltd
The main feedback we received from Maximator was similar to NSW fire and rescue in that simplicity of a visual output was essential. However, Maximator provided input previously not considered such as materials used.
What did we learn for our prototype?
- Easy to interpret visual outputs are welcomed, particularly if it increase efficiency for users responsible for safety checks and maintenance
- User friendly
- Specialised stainless steel to overcome hydrogen embrittlement
- Placement of sensor within a room
- Consider pressure range
How did we integrate the feedback?
- A problem Maximator currently face is hydrogen embrittlement, with hydrogen gas degrading their current sensors. For this reason, a prototype made out of austenitic stainless steel or similar material would be of benefit.
- It was suggested to us that a detector would get different reading depending on the position of the detector in a room. To combat this, industrial settings would benefit from a smoke alarm type detector placed on the roof. The detector would be the most beneficial placed high due to hydrogen gases high dispersal rate and lightweight properties.
BOC
BOC gave the team two overall prototype designs that could be implemented.
What did we learn for our prototype?
- Sticker design
- Cost effectiveness
- Reversibility
- Specificity- Dual purpose sensors tend to be less accurate
- Active or passive drawing of hydrogen gas into the sensor?
- Alarm
- Will the sensors max out at a certain hydrogen gas concentration?
- Cost would not be an issue, particularly if the sensor is needed for maintaining safety regulations
How did we integrate the feedback?
- The first design suggested to us was a sticker as seen in ANSTO (Australia’s Nuclear Science and Technology Organization) for radiation. Our E.coli with GFP would be present on the surface of the sticker, with a breathable plastic covering over the top for biosafety. This design encourages portability, and allows detection anywhere.
- The second design is a results of the emphasis placed on an alarm system. The alarm used in this design could be an infrared point sensor, which will detect the specific wavelength given out by the fluorescence of a positive read from our E.coli.
- BOC also suggested we consider if our detector will be active or passive detection. This detector would be characterized as passive detection, because it does not require an external source of power to draw in the gas being detected. Active detection could easily be achieved if desired by implementation of an extractor fan.