Title: Containment assembly
Abstract: A containment assembly such as a down flow containment assembly including a barrier means between the processing zone and the operator breathing zone at least a first part of which is provided with flexible gloves for access to and maneuverability in the processing zone.
Patent Number: 7,017,306 Issued on 03/28/2006 to Ryder
| Inventors:
|
Ryder; Martyn (Brighouse, GB)
|
| Assignee:
|
Carlisle Process Systems Limited (Dorset, GB)
|
| Appl. No.:
|
029537 |
| Filed:
|
December 21, 2001 |
Foreign Application Priority Data
| Current U.S. Class: |
52/36.1; 52/36.2; 52/39; 52/63; 312/1 |
| Current Intern'l Class: |
A47F 3/02 (20060101); A61L 9/00 (20060101) |
| Field of Search: |
52/361,362,39,63,508,741.3,741.4,DIG.17
454/187,57,58,52
312/1,3,4
160/102,332
134/177,6
588/249
220/350
|
References Cited [Referenced By]
U.S. Patent Documents
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| 3576206 | Apr., 1971 | Trexler.
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| 3709210 | Jan., 1973 | Matthews.
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| 3744055 | Jul., 1973 | Brendgord.
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| 3802416 | Apr., 1974 | Cazalis.
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| 4304224 | Dec., 1981 | Fortney.
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| 4335712 | Jun., 1982 | Trexler.
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| 4485489 | Dec., 1984 | Pilie et al.
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| 4676144 | Jun., 1987 | Smith, IIi.
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| 4817644 | Apr., 1989 | Holmes et al.
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| 4850380 | Jul., 1989 | Koslow.
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| 4911191 | Mar., 1990 | Bain.
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| 4920768 | May., 1990 | Cares et al.
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| 5133246 | Jul., 1992 | Campbell.
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| 5195922 | Mar., 1993 | Genco.
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| 5276252 | Jan., 1994 | Biros et al.
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| 5542463 | Aug., 1996 | Pinkalla et al.
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| 5563066 | Oct., 1996 | Buchanan.
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| 5824161 | Oct., 1998 | Atkinson.
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| 5997399 | Dec., 1999 | Szatmary.
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| 6264055 | Jul., 2001 | Dozier.
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| 6461290 | Oct., 2002 | Reichman et al.
| |
| Foreign Patent Documents |
| 0 195 703 | Sep., 1986 | EP.
| |
| 2215260 | Sep., 1989 | GB.
| |
| 2 261 500 | May., 1993 | GB.
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| 2 262 968 | Jul., 1993 | GB.
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| 194042 | Aug., 1991 | JP.
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| 157301 | Jun., 1993 | JP.
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| 332588 | Dec., 1993 | JP.
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| 101881 | Apr., 1994 | JP.
| |
| 272921 | Sep., 1994 | JP.
| |
Primary Examiner: A; Phi Dieu Tran
Attorney, Agent or Firm: Berenato, White & Stavish LLC
Claims
What is claimed is:
1. A down flow containment assembly comprising:
a powder handling booth of sufficient size to admit an operator, said powder
handling booth having a rear wall, a floor for permitting the operator to stand
thereon, and an upper surface;
a barrier means positioned in the powder handling booth and spaced apart from
the rear wall to define a processing zone between the barrier means and the rear
wall, wherein the barrier means extends from the upper surface at least to the
floor of the powder handling booth, the barrier means comprising a front sheet
and at least one side sheet, and at least a first part adapted or adaptable to
permit the operator in the powder handling booth outside the processing zone to
operate inside the processing zone, the first part comprising a flexible material
extending at least to the floor and an excess of the flexible material resting
directly on the floor, the flexible material comprising an untethered lower edge
and a flexible portion in the shape of a glove or capable of being deformed into
the shape of a glove; and
means for inducing air flow downwardly in the powder handling booth,
wherein the rear wall has a lower end and an upper end and is adapted at or near
the lower end to transmit externally an air flow and adapted at or near to the
upper end to transmit internally the air flow.
2. A containment assembly as claimed in claim 1, wherein more than the first
part of the barrier means comprises a flexible material.
3. A containment assembly as claimed in claim 1, wherein substantially the whole
of the barrier means is composed of flexible material.
4. A containment assembly as claimed in claim 1, wherein the barrier means comprises
a screen barrier.
5. A containment assembly as claimed in claim 1, wherein the barrier means comprises
an enclosure barrier.
6. A containment assembly as claimed in claim 5, wherein the at least one side
sheet comprises, a first side sheet and a second side sheet, and wherein the enclosure
barrier encloses the processing zone when the enclosure barrier is positioned in
the powder handling booth spaced apart from the rear wall.
7. A containment assembly as claimed in claim 6, wherein substantially the whole
of the front sheet is composed of the flexible material.
8. A containment assembly as claimed in claim 6, wherein substantially the whole
of the first side sheet is composed of the flexible material.
9. A containment assembly as claimed in claim 6, wherein at least the front sheet
is adapted or adaptable to permit the operator in the powder handling booth outside
the processing zone to operate inside the processing zone.
10. A containment assembly as claimed in claim 1, wherein the barrier means is
bound within a rigid framework to define a self-contained unit.
11. A containment assembly as claimed in claim 1, wherein the at least one flexible
portion in the shape of a glove or capable of being deformed into the shape of
a glove comprises a flexible sleeve terminating in a gloved end.
12. A containment assembly as claimed in claim 1, wherein the barrier means is
at least partially transparent.
13. A containment assembly as claimed in claim 12, wherein the at least partially
transparent flexible barrier means comprises a transparent window at or near to
a typical operator's eye height.
14. A containment assembly as claimed in claim 1, wherein the flexible material
resting directly on the floor on which the operator is permitted to stand is situated
outside of the processing zone.
15. A down flow containment assembly comprising:
a powder handling booth of sufficient size to admit an operator, said powder
handling booth having a rear wall, a floor for permitting the operator to stand
thereon, and an upper surface;
a barrier means comprising a curtain-type screen barrier, positioned in the powder
handling booth and spaced apart from the rear wall to define a processing zone
between the barrier means and the rear wall, wherein the barrier means extends
from the upper surface at least to the floor of the powder handling booth, the
barrier means comprising a front sheet, and at least one side sheet, and at least
a first part adapted or adaptable to permit the operator in the powder handling
booth outside the processing zone to operate inside the processing zone, the first
part comprising a flexible material extending at least to the floor and an excess
of the flexible material resting directly on the floor, the flexible material comprising
an untethered lower edge and a flexible portion in the shape of a glove or capable
of being deformed into the shape of a glove; and
means for inducing air flow downwardly in the powder handling booth,
wherein the rear wall has a lower end and an upper end and is adapted at or near
the lower end to transmit externally an air flow and adapted at or near to the
upper end to transmit internally the air flow.
16. A containment assembly as claimed in claim 15, wherein the flexible material
resting directly on the floor on which the operator is permitted to stand is situated
outside of the processing zone.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a containment assembly (e.g., a down flow containment
assembly) comprising a barrier means at least a first part of which is composed
of flexible material, and to the barrier means itself.
2. Description of the Related Art
A conventional containment assembly comprises a powder handling booth of sufficient
size to admit an operator for the purposes of handling (for example) pharmaceuticals
or chemicals in a processing zone. The air quality in and around the processing
zone may be controlled using forced ventilation. One category of forced ventilation
is "down flow" in which surrounding air is pushed downwardly to entrain airborne
particles to a level below the processing zone (e.g., to a level below the typical
operator's breathing zone). For down flow containment, exhaust is usually carried
out at low level relative to the source of particles. Current Good Manufacturing
Practices exercised within the pharmaceutical manufacturing industry demand good
containment performance and acceptable operator exposure levels.
A traditional down flow containment assembly is illustrated schematically in
FIG.
1
a (with air flow denoted A) for the purposes of (for example) handling
a pharmaceutical powder within a powder drum
3. An operator
2 is
subjected to exposure levels in the operator breathing zone
1 typically
in the range 150 to 1000 μg/m
3 (and possibly higher). In order
to improve containment and to reduce exposure of operator
2 to airborne
powder in the operator breathing zone
1, it has been known since about 1990
to isolate the operator's position by fitting a work station
4 into the
down flow containment assembly (see FIG. 1
b). The work station
4
typically reduces operator exposure levels to about 50 μg/m
3.
In a more recent development (see FIG. 1
c), a transparent rigid screen
6
of a "salad bar" type has been found to improve exposure levels in the operator
breathing zone
1 to about 10 μg/m
3. The salad bar screen
6 allows the operator
2 to manipulate the powder through a gap between
the work station
4 and the salad bar screen
6.
Notwithstanding these significant improvements, the pharmaceutical
industry is striving for the effectiveness of a down flow containment assembly
to be improved so that the exposure level in the operator breathing zone is less
than 10 μg/m
3. Moreover, with a conventional down flow assembly,
there remains a significant risk of high localized contamination of (for example)
the operator's hands or clothing which is quite unacceptable for handling pharmaceuticals
or chemicals. Added to this, the work station and work station/salad bar developments
restrict access to (and maneuverability in) the processing zone and are particularly
prohibitive to unusually short or tall operators.
Objects of the Invention
The present invention seeks to improve operator exposure levels in a containment
assembly (e.g., a down flow containment assembly) by providing a barrier means
between the processing zone and the operator breathing zone. This is achieved without
hindering the access to (or the maneuverability in) the processing zone of an operator
of any height.
SUMMARY OF THE INVENTION
Thus viewed from one aspect the present invention provides a containment assembly
comprising a powder handling booth of sufficient size to admit an operator, the
powder handling booth having a rear wall, a floor and an upper surface. The containment
assembly further comprises a barrier means at least a first part of which (preferably
substantially the whole of which) is composed of flexible material. The barrier
means is positioned in the powder handling booth and spaced apart from the rear
wall to define a processing zone between the barrier means and the rear wall. The
first part of the barrier means is adapted (or is adaptable) to permit the operator
in the powder handling booth outside the processing zone to operate inside the
processing zone.
It has been surprisingly found that the barrier means of the invention reduces
operator exposure levels significantly beyond the 10 μg/m
3 threshold
desired by the pharmaceutical industry (typically to a level in the range 1 to
5 μg/m
3) whilst ensuring no localized contact with the materials
being handled. The barrier means may be installed within minutes by an unskilled operator.
In a preferred embodiment, more than the first part of the barrier means is composed
of flexible material. Particularly preferably, substantially the whole of the barrier
means is composed of flexible material which maximizes the degree of freedom available
to the operator for operating within the processing zone.
The barrier means may be a screen barrier (e.g., a curtain-type screen barrier),
at least the first part (preferably more than the first part) of which is composed
of flexible material. Preferably substantially the whole of the screen barrier
is composed of flexible material.
The barrier means may be an enclosure barrier (e.g., a curtain-type enclosure
barrier) at least the first part (preferably more than the first part) of which
is composed of flexible material. Preferably, the enclosure barrier consists essentially
of a front sheet, a first side sheet and optionally a second side sheet which when
positioned in the powder handling booth spaced apart from the rear wall defines
an enclosed processing zone. Preferably substantially the whole of the front sheet
is composed of flexible material (and particularly preferably substantially the
whole of the first side (and optionally the second side sheet) is additionally
composed of flexible material). Preferably the front sheet (and optionally the
side sheet) is adapted (or is adaptable) to permit the operator in the powder handling
booth outside the processing zone to operate inside the processing zone.
The barrier means typically extends at least between the upper surface and the
floor of the powder handling booth. The barrier means may be fitted at its lower
edge to the floor of the powder handling booth. Preferably the barrier means at
or near to its lower edge is untethered and extends into an excess of flexible
material. This advantageously makes the first part of the barrier means vertically
moveable (without compromising the improvement in exposure levels) to suit unusually
short or tall operators.
The barrier means may be fitted at or near to its upper edge permanently or non-permanently
to the upper surface (e.g., the ceiling) of the powder handling booth in any convenient
manner (e.g., using suitable fixings or adhesive). Specific examples of fixings
include hooks or Velcro. The barrier means may be fitted at or near to one (or
both) of its vertical side edges to the rear wall in a similar manner. Alternatively,
the barrier means may be bound within a rigid framework to define a self-contained unit.
In a preferred embodiment, the first part of the barrier means comprises one
(or
more than one) flexible portion in the shape of a glove (or one (or more than one)
flexible portion capable of being deformed into the shape of a glove). Particularly
preferably the first part of the barrier means comprises more than one flexible
portion in the shape of a glove (or capable of being deformed into the shape of
a glove). Typically the first part of the barrier means comprises four flexible
portions in the shape of a glove (or capable of being deformed into the shape of
a glove).
In a preferred embodiment, the (or each) flexible portion in the shape of a glove
(or capable of being deformed into the shape of a glove) comprises a flexible sleeve
terminating in a gloved end. Preferably in use the flexible sleeve extends from
the remaining part of the barrier means to beyond the operators elbow (to optimise
maneuverability). The gloved end is typically composed of less flexible material
than the flexible sleeve. For example, the gloved end may be composed of thicker
polyurethane than that of the flexible sleeve (or alternatively of thicker PVC
or other material).
The gloved end may be attached to the flexible sleeve in any conventional manner.
Preferably the joint between the gloved end and the flexible sleeve comprises an
internal strengthening ring to which the ends of the gloved end and the flexible
sleeve are secured. For example, the ends of the gloved end and the flexible sleeve
may be secured to the internal strengthening ring by an elastic band or the like.
At the joint of the (or each) flexible portion in the shape of a glove (e.g.,
the flexible sleeve) and the remaining part of the barrier means, there may be
a strengthening portion (e.g., a strengthening ring or a thickened portion of material).
Typically the position and orientation of the (or each) flexible portion
in the shape of a glove may be tailored to suit the particular operation conducted
in the processing zone (e.g., in accordance with a particular machine which it
is desired to operate).
The flexible material may be polyurethane or polyvinylchloride (PVC). In a preferred
embodiment, the flexible material is polyurethane. Preferably the polyurethane
is sufficiently thin to be effectively transparent. Generally speaking, the (or
each) flexible portion in the shape of a glove is of thicker polyurethane (or PVC)
to guard against tearing.
The barrier means may be fully or partially transparent. For example, the at
least partially transparent flexible barrier means may comprise a transparent window
at or near to a typical operator's eye height (or other heights as desired).
Preferably the powder handling booth is of box-like configuration having
a rear wall, a floor and an upper surface (e.g., a ceiling).
In a preferred embodiment, the containment assembly is a down flow containment
assembly further comprising means for inducing air flow downwardly in the powder
handling booth, wherein the rear wall is adapted at or near its lower end to transmit
externally an air flow and adapted at or near to its upper end to transmit internally
the air flow. For example, the rear wall may be adapted at or near to its upper
end with a ceiling through which air is transmitted.
The containment assembly may be of the down flow type disclosed in UK Patent
application number 0009295.7 (Extract Technology Limited). For example, the powder
handling booth may be a powder handling booth of box-like configuration having
a rear wall positioned adjacent to a modular structure, wherein the modular structure
is adapted at or near to its lower end to receive the airflow from the powder handling
booth and at or near to its upper end to transmit the airflow to the powder handling
booth, and the rear wall of the powder handling booth is adapted at or near to
its lower end to transmit the airflow to the modular structure; and means for inducing
the airflow downwardly in the powder handling booth.
The modular structure may be tailored to meet the requirements and conform to
the size of a desired internal component. Examples of internal components may include
part of the means for inducing the airflow such as, inter alia, one or more filters
or a fan unit. For example, one or more filters may be housed in a lower part and
a fan unit in an upper part of the modular structure. If desired, the modular structure
may be panelled. Suitable panels include standard pressed or vacuum formed filter
retainer panels. Panels may be attached using a proprietary adhesive tape and adhesive
liquid seal to eliminate any tendency for product entrapment whilst giving overall
structural rigidity. The adhesive tape provides a seal for the panel and the liquid
adhesive seal ensures a substantially leak-free joint. The modular structure may
be fabricated from aluminium extrusions joined in a conventional manner (e.g.,
permanently joined with an air tight corner piece) and may (for example) be adapted
to vertically mount a filter such as a pre-filter (e.g., by incorporating a filter
retainer panel) or to horizontally mount a filter such as a hepafilter at its lower
end or to mount a fan unit at or near to its upper end.
In an embodiment of the containment assembly of the invention, the modular structure
comprises an at least partially open front face at or near to its lower end and
adjacent to the rear wall of the powder handling booth, wherein the rear wall of
the powder handling booth at or near to its lower end comprises an elongated gap
capable of transmitting air flow from the powder handling booth to and through
the at least partially open front face of the modular structure. The at least partially
open front face may be adapted to mount a prefilter (e.g., by incorporating a filter
retainer panel).
In an embodiment of the containment assembly of the invention, the means for
inducing
the airflow comprises a fan unit driven by a flange mounted inverter controlled
motor which ensures smooth drive via a flexible coupling. The fan motor unit is
placed down flow from the filters ensuring that the unit is only exposed to clean
filtered air. The fan unit may be seated on highly compressed anti-vibration mounts
to ensure that no vibration is passed onto the adjacent parts of the booth.
Typically, the containment assembly of the invention is adapted so that
air falls in an undisturbed, non-turbulent manner past the operator breathing zone
at a predetermined velocity. Preferably the components of the assembly are adapted
to attain perfect laminar flow (PLF) of air.
An embodiment of the containment assembly of the invention further comprises a
plenum arrangement adjacent to an open ceiling of the powder handling booth (e.g.,
a framework), wherein the plenum arrangement is capable of transmitting the airflow
from at or near to the upper end of the rear wall (or the modular structure) downwardly
into the powder handling booth. The plenum arrangement may comprise one or more
plenum chambers. The one or more or each chamber may be generally adapted to minimize
the plenum volume. Preferably the one or more or each plenum chamber is adapted
to contribute to perfect laminar flow (PLF).
The one or more or each plenum chamber may consist of only one external seal
and is advantageously constructed without external sealants thereby eliminating
a source of possible contamination whilst maintaining the desired level of cleanliness.
The one or more or each plenum chamber may be detachable mounted to the ceiling
of the powder handling booth (e.g., is a plug-in/plug-out arrangement) making it
sufficiently versatile to be attached to any type of powder handling booth. The
one or more or each plenum chamber may comprise a metal (e.g., steel) base frame
coated on two sides with a material of a preset tension. The base frame provides
a specific pressure drop which may contribute to the perfect laminar flow (PLF).
The base frame conveniently has a ladder-like configuration. For example, the base
frame comprises two elongated side members joined in parallel spaced apart relationship
by a plurality of transverse members. On the lower face of the base frame there
may be mounted PLF material (e.g., a PLF screen). Laminar flow light fittings may
be mounted to the lower face of the frame (e.g., the side members) if desired.
A profiled canopy may be secured to the upper face of the base frame. Preferably
the profiled canopy is capable of providing a smooth and interrupted airflow from
the modular structure into the PLF material. For example, the profiled canopy may
have a substantially vertical open end (e.g., a substantially square open end)
through which may be transmitted airflow from a modular structure. The vertical
open end may be defined by two side walls joined in substantially parallel spaced
apart relationship by an integral rear wall which curves inwardly away from the
open end. The vertical open end may be fitted with a compression seal. For this
purpose the ends of the two side walls and integral rear wall may be provided with
a securing flange.
The powder handling booth may incorporate a clean room partition system adapted
to meet the requirements of the pharmaceutical industry. The powder handling booth
may comprise individual panels capable of being locked together thereby advantageously
eliminating the need for fasteners. The powder handling booth may be adapted so
that the number of panel joints are minimized (e.g., 5 or less) and are hygienically
sealed by a thin bead of silicone.
The panels of the powder handling booth may be adapted to provide exceptional
noise damping and vibration isolation. The panels may provide increased rigidity
to support an upper mounted plenum arrangement. The rear wall of the powder handling
booth may comprise a "service band" which may contain, inter alia, control buttons,
the electrical and gauge piping, inverter and commissioning interface which permits
entire commissioning from the interior of the booth. For example, the motor mounted
inverter may be controlled via a link from the service band for ease of commissioning
and set up. Preferably the service band has an aerofoil shaped exterior profile
which improves dust capture in the processing zone by accelerating airflow over
its surface.
Viewed from a further aspect the present invention provides a barrier means
as hereinbefore defined.
The barrier means preferably permits the level of exposure to airborne dust of
an operator in an operator breathing zone to be less than 10 μg/m
3.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described in a non-limitative sense with reference
to the accompanying FIGS. in which:
FIG. 1(
a) illustrates a known down flow containment assembly;
FIG. 1(
b) illustrates the down flow containment assembly of FIG. 1(
a)
fitted with a work station;
FIG. 1(
c) illustrates a the down flow containment assembly of FIG. 2(
a)
with the addition of a transparent rigid screen;
FIG. 2
a illustrates schematically a plan view of an embodiment of the
containment assembly of the invention;
FIG. 2
b illustrates schematically a side view of the same embodiment
illustrated in FIG. 2
a;
FIG. 3 illustrates an embodiment of the barrier means of the invention;
FIG. 4 illustrates a perspective view of an embodiment of the containment assembly
of the invention; and FIG. 5 illustrates the same perspective view of the embodiment
of FIG. 4 with the operator outside the processing zone.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS AND METHODS
With reference to FIGS. 2
a and
2b, there is illustrated
schematically an embodiment of the containment assembly according to the invention.
The containment assembly designated generally by reference numeral
1 comprises
a powder handling booth
2 of box-like configuration having a rear wall
3,
a ceiling
12, a floor
13 and a side wall
14. In this embodiment,
the powder handling booth
2 is a down flow containment booth in which the
extraction fans and filters (and other necessary components)
4 are located
to the rear of the rear wall
3. A down flow of air (A) in the containment
zone is generated by the clockwise circulatory action of the fans and filters
4.
An enclosure barrier
5 has a front sheet
5a and a side sheet
5b extending substantially from ceiling
12 to floor
13
which (when placed against the rear wall
3 and side wall
14 of the
powder handling booth
2) defines an enclosed processing zone B in which
the desired operation is conducted (in this case transferring powder from a bin
6 to weighing means
7). The operator
8 is positioned outside
the processing zone B and is able to operate within the processing zone B. The
combined effect of the down flow air A and enclosure barrier
5 reduces exposure
levels in the operator breathing zone (C) to those described in the Example which
follows. The operator
8 is able to carry out the weighing operation by inserting
right and left hands into the flexible gloved portions
9 in the front sheet
5a of the enclosure barrier
5.
An embodiment of a self-contained enclosure barrier is illustrated in isolation
in FIG. 3 and designated generally by reference numeral
1. The enclosure
barrier
1 comprises a flexible front sheet
2 and two perpendicular
flexible side sheets
3a and
3b mounted on a rigid framework
(not shown), each composed almost entirely of flexible polyurethane which is fully
transparent. When placed against the rear wall of a down flow containment booth,
the enclosed region defines the processing zone. An operator positioned outside
front sheet
2 (and therefore externally to the processing zone) is able
to carry out an operation within the processing zone (for example powder weighing)
by inserting each hand into a suitable one of the flexible sleeves terminating
in gloved ends
4a,
4b,
4c and
4d.
Each of the flexible sleeves terminating in gloved ends
4a,
4b
and
4c are situated on the front sheet
2 and the fourth
flexible sleeve terminating in a gloved end
4d is situated on the
side sheet
3a. Each one of the flexible sleeves terminating in gloved
ends
4a,
4b,
4c and
4d is
sufficiently flexible to permit all round articulation.
An embodiment of the containment assembly in the form of an enclosure barrier
2 fitted in a down flow containment assembly is illustrated in FIG. 4 and
designated generally by reference numeral
1. The enclosure barrier
2
comprises a front sheet
3 and a side sheet
4 each composed almost
entirely of flexible polyurethane which is fully transparent. The down flow containment
assembly comprises a rear wall
5 upon which is mounted a service band
6
and a framework ceiling
7 which transmits air flow downwardly into the containment
zone during down flow of air into the powder handling booth. A grilled area
8
at the lower part of rear wall
5 transmits air flow out of the containment
zone during down flow operation. The front sheet
3 is fitted to the ceiling
7 by hooks (not shown) and the side sheet
4 is fitted to the rear
wall
5 by adhesive tape
19 to define an enclosed processing zone
in which is located a powder drum
9 and a bulk powder drum
15 used
as a reservoir to adjust the weight of powder.
The front sheet
3 is untethered at the floor and its lower edge
16
extends into an excess of material. The front sheet
3 comprises three flexible
sleeves
10a,
10b and
10c, each of which
terminates in a gloved end
11a,
11b and
11c
respectively. The side sheet
4 comprises a single flexible sleeve
10d
terminating in a gloved end
11d. Each gloved end is composed
of thicker polyurethane than that of the flexible sleeve. The adjoining ends of
each gloved end and flexible sleeve are secured to an internal strengthening ring
12a,
12b,
12c and
12d by
an elastic band.
The use of the enclosure barrier
2 is shown in FIG. 5. An operator
51
is able to insert a left arm
52 and a right arm (hidden) into flexible sleeves
10c and
10b (respectively) which extend beyond the
elbow until the fingers engage the gloved portions
11c and
11b
respectively. The operator
51 is able to move freely in all directions
and is assisted in vertical movement by the excess material at the untethered lower
edge
15.
EXAMPLE
Factory Acceptance Testing of a Vacuum Transfer Down flow Booth
Two occupational hygiene (OH) air sampling surveys of the breathing zone and
area air were conducted during factory acceptance testing (FAT) of a down flow
booth (DFB) at Extract Technology Limited in Huddersfield, UK. The DFB is intended
to be used for vacuum transfer of API from kegs. The primary objective of the surveys
was to assess the effectiveness of the DFB compared with the design criteria of
10 μg/m
3 as measured in the operator's breathing zone during routine operations.
Protocol
Samples were collected using 25 mm IOM sampling head and glass fiber filters
and calibrated Gilian air sampling pumps. Lactose was used as the placebo for the
survey. An American Industrial Hygiene Association (AIHA) accredited laboratory
(National Loss Control Service Corporation (NATLSCO)) analyzed the samples using
the lactose OH sampling and analytical method.
To prepare the area for air sampling, a plastic enclosure was installed to enclose
the DFB and isolate the DFB from the rest of the manufacturing environment. The
enclosure was designed to minimize the potential for cross contamination.
Prior to conducting the first survey, modifications to the DFB and equipment
were made which included:
- Installation of a vacuum transfer system (compressor and lance)
- Changes to the height of the local exhaust ventilation and width of
the slot
- Installation of a LEV blower with greater capacity
- Changes to the height of the drum (installation of false bottoms)
After the first survey, a further modification was made to incorporate a flexible
polyurethane curtain having four glove ports within the powder handling booth surrounding
the general processing zone. This formed the basis of the second survey.
Sample Collection—Breathing Zone
Air samples from the breathing zone were collected to assess the effectiveness
of the DFB and vacuum transfer system in maintaining exposures below the target
of 10 μg/m
3. The initial samples were collected from the operator
and assistant operator.
During the first survey, three transfer campaigns consisting of 450 kg of
lactose were performed. For the first two batches, the sample filters were changed
approximately half way through the transfer process. For the third batch, the same
filter was used to assess the operator's exposure throughout the transfer. During
the second batch, a salad bar screen was installed to evaluate the potential for
improvement in exposure levels.
During the second survey, two transfer campaigns consisting of 210 kg of lactose
were performed. For the first batch, the sample filters were changed approximately
two thirds of the way through the transfer process. For the second batch, the same
filter was used to assess the operator's exposure throughout the transfer.
Although the incorporation of the flexible polyurethane barrier within the
booth required some changes in the operating procedures, wherever possible similar
procedures were adopted.
Sample Collection—Area Air
In both surveys, the area air samples were collected in two different locations.
One sample was collected inside the DFB enclosure in the back corner outside the
containment zone. The second sample was collected outside the DFB enclosure. The
sample collected outside the DFB provides an indication of background lactose levels
and potential for false positives.
Operator Breathing Zone Results
Survey 1 (Table 1-1)
All 10 operator breathing zone air samples exceeded the target of 10 μg/m
3.
The sampling results ranged from 12 μg/m
3 to 2400 μg/m
3
with a mean of 415 μg/m
3. There was very little difference
between the samples collected with and without the salad bar screen.
Survey 2 (Table 1-2)
2 out of the 6 air samples from the operating breathing zone exceeded the target
of 10 μg/m
3. The sampling results ranged from 2.1 μg/m
3
to 12 μg/m
3 with a mean of 6.8 μg/m
3.
Area Air Results
Survey 1 (Table 2-1)
The five area air sampling results ranged from 0.59 μg/m
3 to
11 μg/m
3.
Survey 2 (Table 2-2)
The four area air sampling results ranged from <0.14 μg/m
3 to
110 μg/m
3
Conclusions
Survey 1
All the operator breathing zone results exceeded the target concentration of
10 μg/m
3 for both the operator and assistant operator.
If background levels of lactose presented a positive interference the impact
was
marginal because the area air results were significantly lower then the operator
breathing zone results.
Survey 2
The addition of the flexible polyurethane curtain within the booth surrounding
the general processing area and the associated work practices significantly reduced
the operator exposure levels.
The background levels of lactose were much higher and this was most probably
a consequence of poor containment within the lactose receiving area. The results
suggest that the flexible curtain affords a higher degree of protection. Given
the high background levels, the different amount of lactose transferred, the different
times of transfer and the different operators, it is difficult to quantify the
improvement with confidence.
| TABLE 1-1 |
|
| |
|
|
Concentration |
| Sample # |
Activity |
Duration |
μg/m3 |
|
| |
| 20036906 |
Assistant Operator/DFB Vacuum |
28 |
76 |
| |
Transfer - 225 kg lactose |
| 20036911 |
Assistant Operator/DFB Vacuum |
25 |
250 |
| |
Transfer - 225 kg lactose |
| 20036914 |
Operator/DFB Vacuum Transfer |
25 |
140 |
| |
225 kg lactose |
| 20036919 |
Operator/DFB Vacuum Transfer |
27 |
110 |
| |
225 kg lactose |
| 20036910 |
Operator/DFB Vacuum Transfer |
16 |
92 |
| |
225 kg lactose - salad bar |
| 20036925 |
Operator/DFB Vacuum Transfer |
22 |
2400 |
| |
225 kg lactose - salad bar |
| 20036926 |
Assistant Operator/DFB Vacuum |
16 |
200 |
| |
Transfer - 225 kg lactose - salad |
| |
bar |
| 20036922 |
Assistant Operator/DFB Vacuum |
21 |
400 |
| |
Transfer - 225 kg lactose - salad |
| |
bar |
| 20036909 |
Operator/DFB Vacuum Transfer |
29 |
470 |
| |
450 kg lactose |
| 20036915 |
Assistant Operator/DFB Vacuum |
27 |
12 |
| |
Transfer - 450 kg lactose |
|
| Lactose limit of detection = 0.02 μg (20 ng) |
| TABLE 1-2 |
|
| |
|
|
Concentration |
| Sample # |
Activity |
Duration |
μg/m3 |
|
| |
| 20057128 |
Operator/DFB Vacuum Transfer |
24 |
4.4 |
| |
70 kg lactose |
| 20057129 |
Operator/DFB Vacuum Transfer |
51 |
9.3 |
| |
210 kg lactose |
| 20057130 |
Assistant Operator/DFB Vacuum |
42 |
2.1 |
| |
Transfer - 140 kg lactose |
| 20057132 |
Assistant Operator/DFB Vacuum |
51 |
11 |
| |
Transfer - 210 kg lactose |
| 20057134 |
Assistant Operator/DFB Vacuum |
23 |
12 |
| |
Transfer - 70 kg lactose |
| 20057135 |
Operator/DFB Vacuum Transfer |
41 |
2.2 |
| |
140 kg lactose |
|
| Lactose limit of detection = 0.02 μg (20 ng) |
| TABLE 2-1 |
|
| |
|
|
Dur- |
Concen- |
| |
|
|
ation |
tration |
| Sample # |
Type |
Location/Activity |
(min) |
μg/m3 |
|
| |
| 20036907 |
Area |
Outside DFB enclosure in front of |
54 |
0.59 |
| |
|
door/lactose vacuum transfer inside |
| |
|
DFB |
| 20036920 |
Area |
Inside DFB enclosure on post in |
55 |
3.1 |
| |
|
front of DFB next to TSI/lactose |
| |
|
vacuum transfer inside DFB |
| 20036927 |
Area |
Outside DFB enclosure in front of |
41 |
11 |
| |
|
door/lactose vacuum transfer inside |
| |
|
DFB |
| 20036905 |
Area |
Inside DFB enclosure on post in |
40 |
3.9 |
| |
|
front of DFB next to TSI/lactose |
| |
|
vacuum transfer inside DFB |
| 20036928 |
Area |
Inside DFB enclosure on post in |
28 |
7.6 |
| |
|
front of DFB next to TSI/lactose |
| |
|
vacuum transfer inside DFB |
|
| Lactose limit of detection = 0.02 μg (20 ng) |
| TABLE 2-2 |
|
| |
|
|
Dur- |
Concen- |
| |
|
|
ation |
tration |
| Sample # |
Type |
Location/Activity |
(min) |
μg/m3 |
|
| |
| 20057131 |
Area |
Inside DFB enclosure on post in |
72 |
<0.14 |
| |
|
front of DFB next to TSI/lactose |
| |
|
vacuum transfer inside DFB |
| 20057136 |
Area |
Inside DFB enclosure on post in |
45 |
<0.22 |
| |
|
front of DFB next to TSI/lactose |
| |
|
vacuum transfer inside DFB |
| 20057137 |
Area |
Outside DFB enclosure in front of |
78 |
37 |
| |
|
door/lactose vacuum transfer inside |
| |
|
DFB |
| 99045687 |
Area |
Outside DFB enclosure in front of |
50 |
110 |
| |
|
door/lactose vacuum transfer inside |
| |
|
DFB |
|
| Lactose limit of detection = 0.02 μg (20 ng) |
SUMMARY
The results from the first survey indicated that the exposure level in the operator
breathing zone exceeded the target level of 10 μg/m
3. Modifications
were made by incorporating a polyurethane curtain fitted with gloves into the down
flow booth and this led to a surprising reduction in the level of exposure in the
operator breathing zone.
*
