FOG CARTS PROVE FLEXIBLE ALTERNATIVE TO FIXED DECONTAMINATION SHOWERS
Safety management at Eli Lilly, Kinsale, Rep. of Ireland, was the pioneer in the development
of a new system for containment and prevention of cross contamination during the manufacture
of pharmaceutical powders.
This Lilly facility is a bulk manufacturing plant and the main business is producing
human health medicines on a large scale. In addition it produces the active ingredients
for some animal health care products. All Kinsale products are shipped to finishing plants
around the world where they are converted into final dosage forms such as pills, capsules or
injectibles for use by patients..
The Kinsale processes are designed to be fully contained. However there are occasions when
planned breaks in containment have to be carried out and the new system was conceived for
these circumstances. The concept is based on the use of a purpose-designed 'fog cart',
enabling the operator to be covered by an exceptionally fine fog on exit from a critical
area. Any residues on the surfaces of the PPE worn by the operator are dampened down
and gently encapsulated, so that the disposable Personal Protection Equipment (PPE)
can be safely discarded, with virtually no risk of transferring dust traces beyond
their proper confines.
For process rooms not equipped with permanent decontamination showers, the fog cart
system offers a practical alternative that can be set up without disruption - providing
high levels of containment and safety at a fraction of the cost of a fixed shower
installation.
The fleet of 19 fog carts that came into full operation in November 2002 was the
result of collaboration between the plant's Containment Technologist Tony O'Connell
(who identified the need and came up with the original concept and design) and
Spraying Systems (who designed and manufactured the equipment).
Certain locations within the production floors at Kinsale are fitted with fixed PPE
decontamination showers. For space and operational reasons, with production organised
in small discrete areas, this is not practical everywhere. In some locations with no
shower, spray mist lances were used to reinforce containment measures. But they had
limitations. They needed water supply and they needed a second operator. Moreover,
the heavy mist they generated tended to leave the floor wet and potentially slippery.
A prototype fog cart was designed, built and tested by O'Connell at the Kinsale site,
using components supplied by Spraying Systems. The company was then invited to look
at the prototype and supply a factory build unit. The resulting Spraying Systems
unit is a purpose-made fog shower designed for self-operation by a single person.
The cart carries its own supply of water in a removable stainless steel pressure pot.
Compressed air, from the plant system, is split into two separately regulated streams -
supplying pressure to move liquid to the spray nozzles and to atomise it at the nozzle.
Key components are the two Spraying Systems AirJet Fogger nozzles: they produce a
flow-adjustable dry fog, able to dampen surfaces without wetting them.
Before first use, safety staff set air and liquid pressures. Thereafter, the
individual user needs only to connect the cart to plant air, adjust spray height
if necessary, lay down some adsorbent matting, then start the spray and turn around
gently in the fog for one minute - time enough to cover all surfaces of the PPE.
The system is designed to encapsulate any potential dust on the PPE, not to wash
it, thus making it safe for the user to remove and dispose of the clothing safely.
At its low working pressure and flow rate, the 19 litre pressure pot holds enough
water to give more than 2 hours fogging. When it needs filling, or when the whole
shower assembly has to be removed from a working area, it is easily washed down
using the trigger jet spray gun which is also built in to the cart. The cart,
along with all its components, is CE marked.
As Tony O'Connell observed, the great advantage of the fog cart system is its
flexibility.
"It lets us set up a buffer zone for effective de-contamination almost anywhere,
using existing space and with no provision for plumbing," he said. "We just
mark out on the floor a small, dedicated area next to the exit in each room
and station a fog cart there."
Another benefit is self-operation by the user. "It's more convenient and
easier to validate. And the fogging process itself is quicker." Personal
safety is also improved because the specialised nozzles give more efficient
coverage, while the fog is very light so the floor stays relatively dry.
Following his work at Eli Lilly, Tony O'Connell turned to consultancy and
through his company, Containment Service Providers Co., is introducing
the fog cart concept to other manufacturers in the field. In consequence,
the first newly customised Spraying Systems fog carts are already operating
in a second Irish pharmaceutical plant.
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| Fine fog encapsulates residues on PPE for safe disposal. |
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| A decontamination zone can be set up almost anywhere in the plant. |
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| Spraying Systems fog cart. |
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