Water Permeability

Determination of the rate of flow of water through a given area of the sample or the entire prosthesis under a given hydrostatic pressure.

Also known as integral water permeability or leakage.

Test Procedure

Sample is submerged in clean, filtered water at room temperature to wet the sample prior to testing.

The test temperature is measured and recorded.

Test sample is loaded into the holder, stretching the sample sufficiently without distorting the material.

The pump is turned on and flow is adjusted until a desired  pressure is obtained.

The flowrate of water passing through the sample for a specified period of time is measured and recorded. (under a constant pressure)

The water permeability is calculated and recorded expressed in ml/cm²/min.

Considerations for Testing:

• Material type: synthetic textile (e.g. knitted, woven), synthetic nontextiles (e.g. extruded polymer, expanded polymer), biological (e.g. xenograft, human tissues with and without viable cells),  compound, (i.e. other than coated), composite, or coated.
• Specific configuration (for tubular vascular grafts): uniform straight, uniform bifurcated, tapered tubular, or other configurations

For testing a given area of the sample:

• Minimum size – The sample must be larger than a minimum size (normally around 2cm x 2cm)
• Multiple Coupons – Determine how many coupons should be tested from a single sample
• Preparing Coupons – Will the client be providing the pre-cut coupons or will ViVitro Labs be preparing the coupons for testing.

Equipment

• Variable Speed Pump
• Sample holding device with specific aperture opening
• Pressure measuring system
• Data Acquisition system
• Calibrated manometer
• Calibrated balance
• Calibrated chronometer
• Calibrated thermometer

Measured Parameters

• Pressure
• Flow rate
• Water permeability = flowrate through the sample / cross-sectional area of the holder aperture

Scope

• Any device using vascular prostheses
• Vascular prosthesis
• Biological, synthetic textile/non-textile materials, non-textile material
• Stent Grafts: SX or BX frame, NiTi, CrCo, SS, Biological tissues, synthetic textile materials/* non-textile material, non-textile material
• Covered stent: SX or BX frame, NiTi, CrCo, SS, Biological tissue, synthetic textile/non-textile * material, non-textile material
• Tubular, bifurcated, branched
• Complete programs and engineering solutions for testing Vascular Prosthesis and any devices using biological, synthetic textile/non-textile materials, non-textile material.

Service Levels

• Fast Track
• Standard Service
• Full Service

Applicable Standards

• ISO 7198:2016
  Cardiovascular implants and extracorporeal systems — Vascular prostheses — Tubular vascular grafts and vascular patches

Related Tests

• Water Entry Pressure
• Porosity – Microscopic

OLE1513