| Requirement | Specifications | Justifications |
|---|---|---|
| Device must measure surface temperature of gluteal tissue | Sensors must measure surface temperatures between -30-50ºC +/- 1ºC | Apply object of known temperature at -30ºC, 24ºC, 50ºC to device. Compare device output temperatures to thermometer measurements of object. N=5 trials. |
| Device must measure interface pressure of gluteal tissue | Sensors must measure interface pressure in range of 0-250 mmHg +/1.0 mmHg Sensors must placed no further than 1 cm apart inside and 3 cm apart outside the ischial tuberosity area | Apply loads of preset weights over defined area to simulate interface pressure of 0, 115, and 250 mmHg, respectively. Measure loads with a scale and area with a ruler. Compare device reported interface pressures with hand calculated pressures. N= 10 trials. Measure distance between sensors with a ruler. N=5 |
| Device must adjust surface temperature of the gluteal tissue. | Device must decrease the temperature at areas of skin contact by 1ºC. | Place object with same dimension of gluteal tissue (based on Human Factors) on the cushion at a temperature of 35 ºC. Allow the device to complete 1 adjustment cycle, then observe the temperature recorded at different locations to confirm reduced temperature by 1.0˚ C. |
| Device must adjust pressure at defined regions of gluteal tissue. | 2.90 cm x 2.90 cm +/- 0.2 cm inside ischial tuberosity area 4.2) 4.90 cm x 4.90 cm +/- 0.2 cm outside ischial tuberosity area Device must adjust pressure when measured average pressure is greater than or equal 115 mmHg +/- 5 mmHg for a 15 minute +/- 1 minute time period. | Apply loads of 12.90 N or higher over 2.90 cm x 2.90 cm +/- 0.2 cm area inside, or loads of 36.85 N or higher over 4.90 cm x 4.90 cm +/- 0.2 cm area outside ischial tuberosity area for 15 minutes using a timer. Remeasure interface pressure over applied load. Confirm that interface pressure reported by device is less than 115 mmHg +/- 5 mmHg. N= 10 trials. |
