Synthetic Blood Penetration Testing: Using Fluid Dispensing Solutions to Determine Surgical Mask Effectiveness

Fluid Dispensing Equipment Supports Synthetic Blood Penetration Testing

In the wake of the novel Coronavirus, Nordson EFD was asked to recommend fluid dispensing equipment for synthetic blood penetration testing for surgical face masks. Medical workers can be exposed to fluids that can transmit the virus and need masks that prevent fluid penetration.

As large quantities of masks were flown to the U.S. and Canada, medical companies needed to make sure these masks would protect workers from a high-velocity stream of blood. They also needed a proper method for testing to comply with the ASTM standard. Once masks were approved, they could then be distributed to hospitals around the country.

Nordson EFD’s fluid dispensing equipment is specified for use in ASTM F1862, which is the standard test method for resistance of penetration by synthetic blood to medical face masks. These tests are being performed across North America to see how blood splatter under high pressure could penetrate various protective clothing.

That said, there are many factors that need to be considered when choosing the best equipment for this type of application. Surface tension, viscosity, and polarity of the fluid all affect the characteristics and the penetration properties of the synthetic blood, so gathering these characteristics beforehand is very important.

The synthetic blood that was being tested for this application was Direct Red 081. This fluid needed to be shot at a horizontal projection with a fixed volume of material and a known viscosity, which was all provided by the medical company. The test method included an 18-gauge dispensing needle that needed to dispense 2 ml of synthetic blood horizontally with fluid velocities exiting the needle at 450, 550, and 635 cm per second for 1-2 seconds at a time.

Another important factor for this test method to be successful was that the resolution and accuracy of the controller timing. It had to be a minimum of 0.01 ± 0.005 seconds. These parameters were preset by the medical company. For this process to work effectively, Nordson EFD had to ensure the recommended products could perform under these specific parameters.

Nordson EFD’s advanced solutions used for surgical mask testing applications include:

725D Piston Valves

This pneumatic valve’s rugged construction features an ultra-high molecular weight (UHMW) polyethylene diaphragm that isolates the wetted components from the actuator and provides long wear. A slight snuff-back at the end of the valve dispensing cycle prevents dripping between shots. This valve can be mounted in any position.

ValveMate 7100 Controller

The ValveMate 7100 controller is a fast, convenient way to adjust valve open time in increments as small as 0.001 seconds, right at the dispensing station. The result is exceptional process control without time-consuming programming or mechanical adjustments that require the production line to be shut down. This controller features microprocessor circuitry for extremely precise control of deposit size. Feed lines can be purged, initial deposit sizes set, and adjustments made quickly and easily.

Analog Gauge Fluid Reservoir

Nordson EFD analog gauge tank reservoirs not only maintain steady fluid pressure, but also prevent fluid contamination and evaporation, and contain fumes. Tanks are available with 0-15 psi (0-1 bar) or 0-100 (0-7 bar) constant-bleed air regulators to handle different fluid viscosities. Select the 0-15 psi (0-1 bar) regulator for low-viscosity fluids and the 0-100 (0-7 bar) regulator for high-viscosity fluids.

In this photo you can see the Nordson EFD dispensing system specified in ASTM F1862. The EFD controller shown below as “VC” is now obsolete. The best suited replacement is our ValveMate 7100.

Nordson EFD is here to help meet all your medical application requirements, whether it be something to help fight COVID-19 or other life-saving devices.

If you have any questions about our surgical mask test dispensing equipment or would like to improve your process, don’t hesitate to email us at [email protected]

Peter Kaminski

Peter Kaminski is an Application Specialist at Nordson EFD. He provides recommendations and solutions to customers throughout Canada and helps with initial systems integration. Peter has more than 12 years of fluid dispensing experience. He joined Nordson EFD in 2007 and is based in Canada.