Stairsafe Stretcher
Phase 2: Design
———————————— HYPOTHESIS
a low-cost stair chair will supplement evacuation efforts during mass casualty incidents.
When Mass Casualty occurs, Primary Responders often intervene before first response teams arrive, yet lack the necessary resources to respond.
During an emergency evacuation, these primary responders need access to assistance devices, such as stair chairs, to help those with mobility impairments to navigate stairwells. These devices are bulky and expensive, and often reserved for EMS/EMT.
I hypothesize that introducing a lower cost alternative to these devices will encourage businesses and organizations to equip their facilities with devices to prepare for MCI scenarios.
ROLE
Senior Thesis Project
Project Lead
TEAM
Katie Bush
(Solo)
DURATION
December, 2023
4 months
Over a period of 14 weeks beginning in August 2023, the project was divided into two phases: Research and Implementation. I collaborated with industry professionals from Battelle, who sponsored the development of the StairSafe Stretcher. The project adhered to the project brief established by Battelle.
———————————— BACKGROUND
In a world shrouded with uncertainty, the presence of potential mass casualty incidents (MCIs) serves as a stark reminder that unforeseen events can occur at any time.
Despite the unpredictability of what lies ahead, it is imperative that we proactively ready ourselves for emergency scenarios.
Within this endeavor, I delve into innovative initiatives aimed at enhancing public-facing emergency preparedness, with the goal of inspiring businesses and organizations to go beyond the basics in anticipation of potential MCIs.
———————————— THE BRIEF
When Mass Casualty occurs, Primary Responders often intervene before first response teams arrive, yet lack the necessary resources to respond.
During an emergency evacuation, these primary responders need access to assistance devices, such as stair chairs, to help those with mobility impairments to navigate stairwells.
These devices are bulky and expensive, and often reserved for EMS/EMT.
How can we produce a lower cost alternative to existing stair chairs that supplement evacuation efforts of primary responders, before first response teams arrive?
WHAT IS A STAIR CHAIR?
A stair chair is a device designed to transport the mobility impaired throughout stairwells.
These devices often take the shape of a chair form, and range in price and function.
Stair chairs allow for the navigation of tight corners and bends that are typical with stairwells.
Traditional stretchers have trouble navigating tight corners or turns due to its large footprint. Additionally, the weight tends to be distributed towards the lower rescuer.
Stair chairs are able to navigate these tight corners due to a smaller footprint, and evenly distributes weight between the rescuers when carried over changing inclinations.
Stair Chair
Traditional Stretcher
Though existing stair chairs are incredibly effective, their high price point makes it difficult for businesses and organizations to budget for. Oftentimes, access to these devices is limited to EMS and first response teams, leaving those on scene helpless in the event of a MCI.
There is an opportunity for the introduction of a low cost, lightweight stair chair that businesses and organizations can implement without compromising their budget.
———————————— EXPLORATION
Various folding mechanisms and functionalities were investigated and gathered to guide ongoing product development.
While some didn't effectively serve the primary purpose of a stair chair, their folding techniques were considered for potential integration into the stair chair design
Different chair configurations were explored through various forms and folding mechanisms, with different considerations in mind:
Quick setup time
Small footprint for easy packability
Flat form to chair form conversion
2 rescuers required
The folding functionality of 2D sketches were explored further through rapid low-fidelity prototyping on a small scale.
A final concept was explored in full scale, using PVC pipe, 3D printed hinges, paper, and a disposable cloth litter.
———————————— FORMATIVE ASSESSMENT
A formative assessment is a low-stakes assessment tool that provides a systematic way to improve and monitor the progress of a design concept.
To explore different key research questions, the design methodology, indicators, sampling strategy, results, and key takeaways are documented within the framework.
Where is flat-to-chair conversion useful?
Methodology: 1:1 scale prototype movement test through different environments with 2 “rescuers”
Indicators: Pausing, Bumping, Slowing down, Converting from flat litter to chair
Sampling Strategy: Sample is untrained in MCI, test conducted within school environment
Results:
Hinges allow for “auto leveling” of injured, movement slowed over stairs, conversion took place “automatically”
Top subject hands slip when converted to chair, hits chair shape on slope, hits litter shape on flat land,
Top folds before bottom at slopes
Storable in car in completely folded shape.
Take Away:
The chair functionality is best used over stairs or harsh slopes
2 rescuers are required to lift off ground
“L” shape is useful for small set of stairs
Smooth, dynamic transition between litter/chair proved reduced cognitive load of rescuers
Design worked best with taller rescuer at bottom (better leveling)
Collapsibility proved useful for transport/storage
How does weight behave in Stair Chair Stretcher?
Methodology: 1:1 scale prototype weight test through different environments with different weight levels with 2 “rescuers” by observing the behavior of the rescuers and the weight itself
Indicators: Weight shifting, falling, staying in place, Rescuers re-gripping, pausing, struggling
Sampling Strategy: Sample is untrained in MCI, test conducted within school environment
Results:
Weight falling forward during flat-to-chair conversion
Weight shifting downwards during conversion to litter
Rescuers using one hand to recenter weight
Take Away:
For “dead weight”, the flat-to-chair conversion leads to sliding and falling forward
Straps or additional securing measures may need to be taken.
———————————— PROJECT DEVELOPMENT
Market research was performed on existing evacuation chairs and stretchers, and ratings were assigned for the following categories:
Visually non-intimidating
Softness
Intuitiveness
Durability
Packability/ Storability
Required Manpower
Manipulatability
Rapid Deployment
Lightweight
———————————— SCENARIO OF USE
While brainstorming the “Who, What, Where, When, Why, How” surrounding the stair chair concept, logistical factors were taken into consideration, such as;
Who is the intended audience?
When would these devices be used?
How are the devices stored?
How many will be stored in one place?
Where are they stored? '
How will people know where they are stored?
How are they carried?
———————————— FORM REFINEMENT
Further refinement was carried out on the stair chair stretcher, as well as a locker to store the devices in.
———————————— APPEARANCE MODEL
A full scale working model was produced to demonstrate the folding functionality of the StairSafe Stretcher.
Three (3) small-scale non-working models were produced to demonstrate the three “states” of the Stairsafe Stretcher: a folded form, chair form, and a flat dorm.
———————————— PRODUCT VIDEO
———————————— FINAL CONCEPT
Introducing the StairSafe Stretcher: A public-facing emergency evacuation stairwell stretcher for movement impaired individuals
The StairSafe mission aims to offer cost-effective equipment that is easily available for use in all public facilities. With the StairSafe system, bystanders feel empowered to respond in the event of a Mass Casualty Incident (MCI) with confidence.
StairSafe wall hooks can be used to mount up to four StairSafe Stretcher devices on a wall. These hooks can be installed in various configurations to meet the needs of a given business or organization.
Wall hooks can be integrated into the StairSafe rolling cart to allow for the transport of multiple stretchers at a time, and conceals the devices when not in use. Signage on the cart sides allows for bystanders to easily locate the system from either side of the cart.
With several different storage options, schools, businesses, and organizations can choose how and where to store the stair stretchers. Implementation is easy and affordable, and allows for strategic integration into any building.
Image sources:
https://www.onestopenglish.com/lessons/environment-natural-disasters/551224.article
https://mil.wa.gov/wildfire
https://www.bbc.co.uk/programmes/p0fjgscx
https://www.hmpgloballearningnetwork.com/site/emsworld/feature-story/medical-mass-casualty-lessons-learned-deadliest-human-smuggling