REAR Lab: Contract Testing
Wheelchair Cushion Tests
- Dimensioning, loaded countour depth, overload depth
- 1st cushion: $500
- 2nd cushion: $250
- 3rd and up: $150 each
- 1 cushion $500
- 2 cushions: $750
- 3 cushions: $900 plus $150 each afterward
- Interface pressure tests - Human Subjects
- 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 SADMERC
- 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 pressure tests - Buttock model
- 1st cushion- $600
- each additional cushion: $300
- Positioning Tests:
- 1st cushion: $250
- each additional cushion: $150
- 1st cushion: $250
- each additional cushion: $150
- 1st cushion- $750
- each additional cushion: $300
- SADMERC Simulated use tests
- 1. Laundering of cover. If the cushion is supplied with a removable cover, it will be exposed to 5 repeated washing and drying cycles
- 2. Accelerated heat aging. The cushion & cover are exposed to 70 °C for 48 hours
- 3. 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.
- 4. 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.
- Advanced Simulated Use Testing
- 1) Loaded contour Depth & Overload Depth testing
- 2) Impact Dampening
- 3) 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.
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.
$350/subject for up to 2 test cushions and one reference foam cushion A 3rd test cushion will add $75/subject Additional test cushions (4+) may require a 2nd test session and, therefore, costs will be determined once the number of cushions is defined.
150/subject for up to 2 test cushions and one reference material A 3rd test surface will add $50/subject Studies with >15 subjects may qualify for reduced rates depending on protocol
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. The ISO buttock model will be used as the indentor and a commercial interface pressure map will be the transducer. Report will include Peak Pressure Index and Dispersion Index calculations. Pressure mat will be calibrated immediately before data collection.
Ability to accommodate pelvic obliquity- a buttock model is loaded in obliquity, and the symmetry of the forces is calculated and compared to a reference cushion.
Positioning features under load:
Buttock models and thigh models are used to impart loading on cushion; the height of positioning features are then measured under load
Cushion adjustability assessment — 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 indentor. 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:
Cost: 1st cushion: $750; each additional cushion: $600
Report: Test results will be tabulated into a single report; raw data will also be provided in a separate report summary.
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)
Measurements:
| Type of Cushion | Protocol | Sub-protocol |
|---|---|---|
| Cushions with Covers | Soiling | |
| Laundering cover (5 washer/dryer cylces) | ||
| Cleaning cushion if urine penetrates cover | ||
| Cyclic Loading | Static | |
| Dynamic | ||
| Cushions without Covers or no cover | Soiling | |
| Cleaning cover with cushion | ||
| Heat aging | ||
| Cyclic Loading | Static | |
| Dynamic |
Cost: 1st cushion: $1000; each additional cushion: $750