Contract Testing: Wheel Chair Cushion Testing
Complete wheel chair cushion testing information including prices are available upon request. Please email firstname.lastname@example.org
- Dimensioning, loaded contour depth and overload depth
- Interface pressure tests:
- Positioning Tests:
- Cushion adjustability assessment
- PDAC HCPS (SADMERC) Simulated use tests
- Advanced Simulated Use Testing
These tests are required for SADMERC coding: Overall height, width, and depth; weight; dimensions of features in a pre-loaded state; loaded contour depth test and overload test performed 3 times with the median values reported.
Wheelchair users. At least ten wheelchair users, five of whom are clinically insensate will be measured while seated on the test cushion and a reference foam cushion. Analysis includes calculation of several variables including the Peak Pressure Index required by the PDA HCPCS
Subjects without disabilities. Measurement of non-wheelchair users is logistically and technical simpler (i.e., recruitment, transferring) but provides much different information about cushions and supporting surfaces.
Interface pressures will be measured under three loading conditions corresponding to 3 body masses, 56, 70 and 84 kg. The ability of a cushion to accommodate different body weights will be compared to a flat reference foam. Cushions will be adjusted for each loading configuration. CATEA has a variety of buttock models that reflect different types of people. Discussion would be needed to identify which model or models would be most useful. The final report will include Peak Pressure Index and Dispersion Index calculations. The pressure sensitive system will be calibrated immediately before data collection.
Instrumented buttock models have been designed to represent different human morphology. Pressures are measured at multiple locations along the model midline. Different loading conditions have been defined to represent persons ranging from 56 to 114 kg. Most often, a flat reference foam is measured in parallel to the test cushions. Pressure metrics are calculated and compared to those metrics measured on a flat reference foam cushion.
The baseline test involves: 1 buttock model at 2 loads and includes reference foam testing
A buttock model is loaded in obliquity, and the symmetry of the forces is calculated and compared to a reference cushion.
Buttock models and thigh models are used to impart loading on cushion; the height of positioning features are then measured under load
Instrumented Buttocks model:
Instrumented buttock model is applied to the cushion using 3 loading conditions representing 56, 70 and 84 kg persons. Two instrumented buttock models, varying in shape, will be the indent or. Pressures are measured at 5 locations along the model midline. Pressure metrics are calculated and compared to those metrics measured on a flat reference foam cushion.
Cushions will be exposed to four separate tests that simulate 12 or 18 months of use. Loaded Contour depth and overload depth tests will be run before and after simulation testing.
The simulated test protocol is as follows:
- Laundering of cover. If the cushion is supplied with a removable cover, it will be exposed to 5 repeated washing and drying cycles
- Accelerated heat aging. The cushion & cover are exposed to 70° C for 48 hours
- Dynamic cyclic loading. The test cushion is repeatedly loaded with 0-750 N. For a 12 month simulation test, 8700 +/- 200 cycles are performed and for an 18 month simulation, 13,000 +/- 200 cycles are performed.
- Static/dynamic cyclic loading. Test cushion is exposed to a 400-600 N cyclic load. For a 12 month simulation test, 35,000 +/-200 cycles are performed and for an 18 month simulation, 52,500 +/- 200 cycles are performed
Report: Test results will be tabulated into a single report; raw data will also be provided in a separate report summary.
Non-Human PDAC Testing (Summary)
Dimensioning, loaded contour depth, overload depth and simulated use tests
Cushions will be exposed to a sequence of simulated use protocols reflecting 12 or 18 months of use. Three tests batteries will be run before and after each cycle (either 12 or 18 months)
- Loaded contour Depth & Overload Depth testing
- Impact Dampening
- Instrumented buttock testing (25.5 model at 70 & 84 kg loading)
Loaded Contour depth and overload depth tests will be run before and after simulation testing.
Advanced Simulated Use Testing
Cushions will be exposed to a sequence of simulated use protocols reflecting 12 or 18 months of use. Three tests batteries will be run before and after each cycle (either 12 or 18 months). Loaded Contour depth and overload depth tests will be run before and after simulation testing.
Simulation protocol sequences
|Cushions with removable covers||Cushion without removable covers (or no cover)|
2. Cleaning cover/cushion