Flexible enclosure design begins with an evaluation of compatibility and configuration.
- Is the film compatible with the process chemicals and operating conditions (temperature, pressure, LEL, venting requirements, connection points, etc.)?
- How much space is available (footprint for flexible enclosure and pass-throughs, headspace, ergonomic safety)?
- Is the primary goal personnel or product protection?
- Will the approach compromise regulatory criteria?
While providing the optimum in design freedom (see examples on our website), for operator acceptance, compliance, and safety are of paramount importance. Having established compatibility the next step is to decide how the flexible enclosure will be manipulated.
Once installed, will a semi-rigid or flexible mounting best serve (operator height and reach, confined space limitations, mobility, enhanced venting)?
Inflatable enclosures of up to 4 ft height offer the simplest and most mobile solution not requiring a support frame.
Cart mounted support frames of PVC or metal offer mobility while restricting headspace.
Freestanding PVC and metal frames are applicable for bench and hood through full manufacturing suite design and installation capability.
When frame support is selected, the frame attachment approach determines the freedom for enclosure manipulation. Options frequently used are:
- Velcro straps bonded into the seams of the enclosure which gives both loose (~2 inches of give) or tight connection with the support frame. The velcro straps are easily released to allow the enclosure to be manipulated e.g., to reduce or increase the internal volume.
- Eyelets bonded to the seams allows for the most forgiving installation using rope or wire of indeterminate length, cable ties, or bungy cords for tethering to the support frame, process piping, or random tie-off points.
- Snap strips bonded into the seam give a robust and rapid way of releasing the enclosure having a firmer connection to frame.
Once compatibility, support system, and mounting options are selected, it remains to finalize the dimensions of the enclosure, the pass-through style (adjoining zippered chamber, cylindrical, or a continuous cylinder), power cord penetrations, and the number and style of gas filters attached to the inlet, and wall mounted exhausts.
It is recommended that operators be involved in the final design to ensure that they have a feeling of ownership and willingness to adopt the new way of processing.
When the design is approved by the user and the vendor it remains to place an order.
The workspace should be cleared and any support framework or cart and utilities e.g., compressed gases, instruments to be installed, and waste collection drains, prepared ready for delivery of the fabricated enclosure.
Installation onto the existing framework, or inflation of the self-supporting enclosure is a simple matter of removing from shipping package, unfolding the enclosure and partial inflation to reveal the shape to orient the enclosure followed by placement and attachment to any framework. Once installed and inflated, the tape seals covering any exhaust filters are removed. Instruments and implements for use are placed inside the pass-through and into the enclosure. Instrument power cables are fed through the respective openings and secured using 3M tape and cable ties, with bonding adhesives as needed.
As described, the enclosure is fully compatible with HAZMAT (FEMA) and RiskMAP (FDA and FEMA) criteria for confinement of solid and small volumes of liquid waste for disposal by incineration.
Written by Brian Ward, PhD, CSci, CChem, FRSC