Safety shield

A safety shield for capturing corrosive fluids escaping from joints or valves in piping systems consists of first and second shroud members releasably joined together to form an enclosed chamber in assembled position about the joint or valve. The chamber includes at least one aperture which is sized and shaped for mating engagement around the pipe. Corrosion resistant gasket members interposed between the first and second shroud members and between the pipe and the at least one aperture render the enclosed chamber vapor tight in the assembled position. The chamber may further include at least one other aperture sized and shaped to receive the operating stem of the valve therethrough, and a corrosion resistant gasket interposed between the valve stem and the at least one other aperture for forming a vapor tight seal without interfering with the operation of the valve. The first and second shroud members are releasably held together by adjustable bands which are tightened around the outer periphery of the shroud members so as to exert a substantially uniform pressure along the joining region between the shroud members. The safety shield may also include one or more outlets for discharging any fluid which may accumulate in the enclosed chamber.

FIELD OF THE INVENTION 
The present invention relates to a safety shield for intercepting leakage 
from piping systems. More particularly, the present invention relates to a 
safety shield which intercepts and contains both liquids and vapors which 
leak from a pipe joint or valve. 
BACKGROUND OF THE INVENTION 
Many factories, such as chemical manufacturing plants and the like, have 
extensive systems of piping which handle corrosive or otherwise hazardous 
fluids. These fluids typically consist of liquids, vapors or combinations 
thereof which travel through the pipes under varying pressures. 
In view of the hazardous nature of these fluids, the integrity of the 
piping systems is critical. Notwithstanding the care exhibited in 
assembling and maintaining these systems, leaks occasionally develop, 
typically in joints between two or more pipes or between pipes and other 
components such as flanges, couplings, valves, expansion joints, gauges 
and the like. In most cases it is imperative that all of the liquid or 
vapor which may escape through these leaks be intercepted and contained 
before causing damage to equipment or, more importantly, to plant 
employees. This need is especially critical in those cases where the 
piping systems are carrying toxic materials, the escape of which would 
present an immediate danger to the health and even the lives of plant 
employees. 
In addition, federal and state environmental regulations, for example, the 
federal Clean Air Act, as well as individual corporate air quality 
programs, seek to control and eliminate, or at least minimize the release 
of harmful materials into the environment. Such releases typically occur 
as standard process emissions or accidental emissions from process 
equipment. Many of the harmful materials these programs seek to control 
are cancer causing agents. Others, vapor emissions in particular, are 
harmful to the earth's ozone layer. Both the federal Environmental 
Protection Agency and the Occupational Safety and Health Administration 
have as their objectives the promotion and regulation of practices which 
minimize uncontrolled vapor and liquid releases by setting program 
guidelines for monitoring, detecting and containing such releases. 
Presently available shields do not provide adequate safeguards to control 
such undesirable releases. Thus, while flexible safety shields, such as 
those disclosed in U.S. Pat. No. 4,106,428 to Matthiessen and co-pending 
application Ser. No. 07/445,176, intercept a stream of liquid which may 
leak from a pipe joint, they do not prevent the liquid from eventually 
dripping or otherwise flowing from the shield. Moreover, these flexible 
safety shields do not contain vapors which may escape through the pipe 
joint. 
Other available safety shields consist of separable portions formed from a 
semi-rigid material which assemble around a pipe joint to form an annular 
chamber thereabout. The members are typically assembled by snapping the 
two portions together to form a loose fit about the pipe joint. Thus, 
since this type of shield does not form a seal around the pipe it is 
simply unable to contain any escaping vapors and only minimally contains 
escaping liquids. Furthermore, the failure of the individual components to 
be positively and securely assembled together presents a hazardous 
condition. Should a significant amount of liquid accumulate in the shield, 
the shield may readily come apart, exposing those persons nearby to its 
contents. Even in those cases when the shield does not come apart under 
the weight of its contents, the need to remove the shield from the pipe 
joint in order to empty its contents exposes maintenance workers to 
potential harm. 
In addition, a majority of the piping systems in use today include one or 
more valves which may be selectively opened or closed in order to control 
the flow of fluids therethrough. These valves are frequently prone to 
leakage, particularly as they become aged and no longer provide an 
effective seal. Notably, none of the safety shields available today are 
capable of accommodating a valve without interfering with its operation, 
while at the same time intercepting and containing any liquid or vapor 
which may leak therefrom. 
Thus, the need exists for an improved safety shield capable of forming an 
airtight seal about pipe joints and about valves in order to intercept and 
contain any liquid or vapor which may leak from piping systems at these 
points. There also exists a need for a safety shield which will surround a 
pipe joint or a valve in a secure fashion and not readily become 
disengaged therefrom. Preferably, the improved safety shield will provide 
adequate safeguards from the release of harmful liquids and vapors in full 
compliance with governmental regulations. More preferably, the improved 
safety shield will enable any contained fluids to be readily drained 
therefrom without subjecting plant employees to their hazardous contents. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, these needs have now been 
addressed by the invention of an improved safety shield for a joint in a 
pipe carrying a fluid. The safety shield consists of first and second 
shroud members joined to form a vapor-tight enclosed chamber in assembled 
position about the pipe joint; connecting means for releasably joining the 
first and second shroud members together; and at least one aperture in the 
chamber sized and shaped to form a vapor-tight seal around the pipe. The 
first and second shroud members are preferably formed from a corrosion 
resistant material, and more preferably from a mixture of fiberglass and 
an organic polymer. The fiberglass preferably comprises between about 10 
wt. % and about 50 wt. % of the mixture; more preferably between about 20 
wt. % and about 40 wt. % of the mixture; and most preferably about 30 wt. 
% of the mixture. 
Corrosion resistant gasket means are desirably included between the shroud 
members to assure the enclosure is adequately sealed. The gasket means 
preferably is in the form of a continuous gasket including first gasket 
members interposed between the joining surfaces of the shroud members and 
second gasket members positioned in the at least one aperture in the 
shroud members for forming a vapor-tight seal between the shroud members 
and the pipe. The first and second gasket members may be formed integrally 
as a single gasket element or may be formed as a plurality of gasket 
elements joined together. 
In preferred embodiments, the first and second shroud members are 
releasably held together in assembled position by one or more adjustable 
straps which encircle the shroud assembly. The use of such straps enables 
the shroud members to be held together with a substantially uniform 
pressure along their joining surfaces. As a result, localized pressures 
which may result in the warping or distortion of the joining surfaces of 
the shroud members are avoided and a more effective seal is created. 
In one embodiment, reinforcing ribs are disposed on at least one surface of 
the shroud members. Preferably, the reinforcing ribs are disposed on both 
the interior surface and exterior surface of the shroud members. In a 
highly preferred embodiment, the shroud members include a pair of spaced 
wall members and an annular surface joining the spaced wall members, and 
the reinforcing ribs are disposed on both the interior and exterior 
surfaces of the spaced wall members and on the annular surface in the 
interior of the shroud members. 
Preferably, the safety shield further includes outlet means for discharging 
any fluid accumulated in the chamber. In those cases where a liquid and a 
vapor may accumulate in the chamber, the outlet means desirably includes a 
first discharge port for discharging the liquid from the chamber, and a 
second discharge port for discharging the vapor from the chamber. 
In embodiments particularly adapted for use in connection with valves 
having a valve body and a valve stem extending outwardly from the valve 
body, the safety shields of the present invention may enclose the valve 
body and include an aperture for accommodating the valve stem and 
corrosion resistant gasket means for forming a vapor tight seal between 
the valve stem and the shroud without interfering with the operation of 
the valve. 
In highly preferred embodiments of the present invention, the safety shield 
further includes devices for determining the physical conditions within 
the enclosure. Desirably, the devices for determining the physical 
conditions within the enclosure include pressure sensing means, fluid 
sensing means wherein the fluid is a liquid and/or a vapor, temperature 
sensing means, and the like. Most desirably, the safety shield in 
accordance with this embodiment will further include alarm means 
responsive to signals generated by these devices. 
Preferred embodiments of the present invention provide an improved safety 
shield wherein dangerous liquids and vapors which may leak from a joint or 
a valve in a piping system may be safely intercepted and contained. The 
safety shield is attached around a pipe joint in a secure fashion which 
will not be readily dislodged. Such safety shield not only satisfies the 
requirements of corporate safety programs, but prevents the undesirable 
release of harmful materials into the atmosphere and thereby facilitates 
full compliance with federal and state environmental regulations. 
Furthermore, preferred embodiments of the present invention provide an 
improved safety shield which permits such contained liquids and vapors to 
be safely drained therefrom, thereby preventing the exposure of 
maintenance workers to such hazardous materials. In addition, the 
reinforced structure of the safety shield permits the attachment of 
various sensing and alarm devices which enhance the safety associated with 
using such shields. 
Moreover, the preferred safety shield according to the present invention 
provides these improvements while at the same time being highly resistant 
to attack by the chemicals carried in the pipeline.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
For the purpose of describing the features of the present invention, one 
embodiment of the improved safety shield is discussed in association with 
a well-known type of flanged pipe coupling typically found in chemical and 
similar industries which handle corrosive or otherwise hazardous fluids. 
As used herein, the term "fluid" refers to materials in any physical state 
which are capable of flowing through piping systems. Generally, the fluid 
materials referred to herein are liquids and/or vapors. 
Such couplings generally include flanged sections having faces lying in 
planes normal to the longitudinal axis of the pipe. In a typical assembly, 
a gasket is inserted between the faces of the flanged sections which are 
then fastened together by bolts to form a liquid-tight joint. Although 
described in association with flanged pipe couplings, it is contemplated 
that the improved safety shield of the present invention may be assembled 
about any joint which may be formed in a piping system. As used herein, 
the term "pipe joint" refers to the seam formed by the assembly of 
individual components of the piping system. Such joints include, but are 
not limited to, the connection between segments of pipe, valves, gauges, 
expansion joints, meters, couplings and the like. 
Fluids flowing through piping systems frequently encounter or create weak 
spots at pipe joints, particularly when they travel under high pressure. 
Such weak spots typically result from the deterioration of or defects in 
the gaskets assembled in the joint. When encountered, such weak spots may 
permit hazardous liquids and vapors to escape from the piping system. 
These liquids and vapors present a substantial danger not only to the 
equipment and personnel in close proximity to the pipe joint, but to the 
environment as well. In those cases where the leaking substance is toxic 
the dangers are magnified. 
Another embodiment of the improved safety shield of the present invention 
is described in association with a valve incorporated in a piping system. 
These valves take many different forms and may be operated either manually 
or automatically. In most cases, however, the valves include a valve body 
and some form of valve element arranged in the valve body for movement 
between positions in which the valve element partially or completely 
obstructs the flow of fluid materials through the valve body and a 
position in which the valve element does not obstruct the fluid material 
flow at all. In most cases, a valve stem connected to the valve element 
and extending outwardly of the valve body provides a mechanism for 
maneuvering the valve element between these positions. A valve stem seal 
is ordinarily provided to prevent the fluid materials coursing through the 
piping system from leaking out from between the valve body and valve stem. 
After repeated use or prolonged exposure to corrosive materials, these 
valve stem seals may fail, enabling the hazardous liquids and vapors 
within the piping system to escape. 
The present invention provides an improved safety shield to intercept and 
contain any fluids, particularly liquids and vapors, which may escape from 
a failed pipe joint or a leaking valve, thereby protecting persons and 
objects in the vicinity of such a leaking component from possible serious 
injury, and protecting the environment from further endangerment. 
Referring to the Figures, safety shield 10 has a generally annular shape 
formed by the assembly of shield members 12 and 14. Typically, shield 
members 12 and 14 are formed from a rigid or semi-rigid impervious 
material which is highly resistant to chemical attack. In some situations 
it is desirable to form shield members 12 and 14 from a flexible material 
such as polyethylene, polytetrafluoroethylene and the like in order to 
accommodate the expansion or other relative displacement of the piping 
system components. In other situations, safety shield 10 may encounter 
relatively high pressures caused in particular by vapors leaking from a 
pipe joint. In these situations, it is preferable to form shield members 
12 and 14 from a more rigid material which will not deform under these 
high pressures and which will therefore render safety shield 10 less 
susceptible to leakage. Preferred materials in this regard include 
polypropylene, stainless steel and other chemically resistant materials. 
More preferably, shield members 12 and 14 are formed from a chemically 
resistant organic polymer base material, such as polypropylene, 
polyethylene or polytetrafluoroethylene, to which fiberglass has been 
added as a reinforcing agent. Preferably, the fiberglass additions 
comprise between about 10 wt. % and about 50 wt. % of the entire 
composition; more preferably between about 20 wt. % and about 40 wt. % of 
the composition; and still more preferably about 30 wt. % of the 
composition. The addition of the fiberglass reinforcement has a negligible 
affect on the chemical resistance of the safety shield. As a result, these 
materials provide a safety shield which is lightweight and which is 
capable of withstanding pressures of about 200 psi or greater. 
Shield member 12 has spaced semi-annular walls 16 and 18 joined together by 
an arcuate portion 20. Opposite arcuate portion 20, shield member 12 has a 
free edge 22, one portion of which includes substantially flat sections 
22a and 22b which lie generally in a plane running through the 
longitudinal axis of safety shield 10 and which define a joining region 
for mating with a similar joining region on shield member 14. Another 
portion of free edge 22 includes section 22c on wall 16 and section 22d on 
wall 18, each of which forms a semicircular path a spaced distance from 
the longitudinal axis of safety shield 10. Each of free edge sections 
22a-d may include a recessed groove 23 for receiving a sealing member as 
will be described more fully below. 
In order to provide safety shield 10 with increased structural rigidity and 
increased resistance to distortion under high internal pressures, shield 
member 12 may be provided with reinforcing structures. In one embodiment, 
annular wall members 16 and 18 may be provided with external reinforcing 
ribs 24 which extend codirectionally between free edge 22 and arcuate 
portion 20. In preferred embodiments, shield member 12 may also include 
reinforcing ribs formed on the interior surfaces thereof. Such ribs may be 
provided in place of or in addition to ribs 24, and may include both 
longitudinal ribs 26 and transverse ribs 28 on the inside surface of 
arcuate portion 20 and ribs 29 extending codirectionally on the inside 
surface of walls 16 and 18 between arcuate portion 20 and free edge 22. 
Forming ribs 24, 26, 28 and 29 with a thickness of about 1/16 inch and a 
depth of about 1/4 inch provides sufficient structural strength without 
interfering with the fit of safety shield 10 around a pipe flange, valve 
or other such joint. 
Shield member 14 may be structurally identical to shield member 12. Thus, 
shield member 14 has spaced semi-annular walls 30 and 32 joined together 
by an arcuate portion 34. Opposite arcuate portion 34, shield member 14 
has a free edge 36. One portion of free edge 36 includes substantially 
flat sections 36a and 36b which lie generally in a plane running through 
the longitudinal axis of safety shield 10 and which define a joining 
region for mating with the similar joining region on shield member 12. 
Another portion of free edge 36 includes section 36c on wall 30 and a 
similar section 36d (not shown) on wall 32, each of which forms a 
semicircular path a spaced distance from the longitudinal axis of safety 
shield 10. Although not shown, free edge sections 36a-d may also include a 
recessed groove for receiving a sealing member, similar to the groove 23 
formed in shield member 12. Again, shield member 14 may be formed with 
reinforcing structures for increasing the structural rigidity thereof. In 
one embodiment, reinforcing ribs 38 may extend codirectionally on the 
external surface of annular wall members 30 and 32 between free edge 36 
and arcuate portion 34. Preferably, the internal surfaces of shield member 
14 may be formed with reinforcing ribs (not shown), such as those 
described above in connection with shield member 12. 
In assembled position around a pipe P, as shown in FIG. 5, shield members 
12 and 14 define aperture 50, the circumference of which is defined by 
free edge sections 22c and 36c, and a similar aperture 52 (not shown), the 
circumference of which is defined by free edge sections 22d and 36d. 
Apertures 50 and 52 are sized to snugly engage the portions of pipe P on 
either side of the flanged pipe coupling. Thus, when used for pipes P 
having a large diameter, safety shield 10 has correspondingly large 
apertures 50 and 52; when pipes P have a small diameter, apertures 50 and 
52 are correspondingly small. 
So that safety shield 10 may provide a liquid-tight and vapor-tight 
enclosure in assembled position about a flanged pipe coupling, a gasket 
assembly 40 is interposed between shield members 12 and 14. A preferred 
gasket assembly 40 is shown in FIG. 4. Gasket assembly 40 includes a first 
U-shaped gasket portion 40a having a round or similar cross-section for 
seating in the groove 23 between free-edge sections 22a and 36a on 
one-half of safety shield 10, and a second U-shaped gasket portion 40b 
having a round or similar cross-section for seating in the groove 23 
between free edge sections 22b and 36b in the other half of safety shield 
10 to seal the joining region between shield members 12 and 14. In an 
alternate arrangement, the cross-section of groove 23 may have a different 
shape, such as rectangular, and U-shaped gasket portions 40a and 40b may 
have a corresponding shape to seat within the groove 23 so as to provide 
an effective seal between shield members 12 and 14. Preferably, gasket 
portions 40a and 40b may include a rib 41 extending along their lengths to 
increase the area of contact between the gasket members and the shield 
members so as to provide an improved seal. 
In order to assure a liquid- and vapor-tight seal about pipe P, aperture 50 
is provided with a gasket member 54. Aperture 52 is provided with a 
similar gasket member 56. Gasket members 54 and 56 are preferably formed 
with a round or similar cross-section for seating within the groove 23 in 
free edge sections 22c and 22d in shield member 12 and in free edge 
sections 36c and 36d in shield member 14. In a particularly preferred 
arrangement, shown in FIG. 4, gasket members 54 and 56 may be formed with 
a rectangular outer surface for seating within a rectangular groove 23, 
and a round inner surface for seating against pipe P. 
So that gasket members 54 and 56 may be assembled about pipe P, these 
gasket members are formed as an elongated strip of gasket material having 
fastening members at the opposite ends thereof. As shown in FIG. 4, one 
end of gasket member 56 is recessed as at 56a and includes a protruding 
nub 56b. The opposite end of gasket member 56 has a tab extension 56c 
which is sized and shaped for mating engagement with recess 56a. An 
aperture 56d in tab extension 56c receives nub 56b to interlock the ends 
of gasket member 56 together. The ends of gasket member 54 are provided 
with a similar fastening mechanism for assembling and holding gasket 
member 54 in place around pipe P. 
Gasket members 54 and 56 also include a pair of hollow bosses 55 and 57, 
respectively, which lie diametrically opposed to one another in the 
assembled position of gasket members 54 and 56. Bosses 55 and 57 are sized 
and shaped to receive the ends of gasket members 40a and 40b for joining 
the several gasket members together into a complete gasket assembly 40. 
Joining the gasket members together in a single assembly assures the 
formation of a continuous seal between shield members 12 and 14 in 
assembled position around pipe P. Gasket members 40a, 40b, 54 and 56 
alternately may be formed as a single integral unit, thereby eliminating 
the need to join the individual gasket members to one another. Preferably, 
gasket members 40a, 40b, 54 and 56 are formed from a material which is 
sufficiently chemically resistant to withstand attack from the corrosive 
liquids and/or vapors which are retained by safety shield 10, but which is 
sufficiently pliable to form a liquid- and vapor-tight seal when safety 
shield 10 is in assembled position about pipe P. An example of one such 
material is polytetrafluoroethylene. 
Shield members 12 and 14 may be securely held in assembled position around 
pipe P by any suitable means. In a preferred embodiment shown in FIG. 5, 
shield members 12 and 14 are held in place by a pair of bands or straps 90 
which encircle and engage the outer periphery of shield members 12 and 14. 
Bands 90 are of the type which is commonly available for clamping around 
substantially round structures and include a threaded fastener 92 which 
can be turned in a clockwise direction in order to tighten the clamping 
pressure of bands 90 around shield members 12 and 14 or turned in a 
counterclockwise direction in order to loosen the clamping pressure of 
bands 90 around shield members 12 and 14 for disassembly. Bands 90 apply a 
substantially uniform radially directed force to shields members 12 and 14 
which creates a substantially uniform pressure distribution along the 
joining region between the shield members. This substantially uniform 
pressure distribution eliminates the warping or other distortion of the 
shield members which typically results when the shield members are joined 
together at discrete locations, such as by nut and bolt fasteners, clamps, 
etc. To assure that the pressure is applied as uniformly as possible 
around the circumference of safety shield 10, the outer surface of arcuate 
portion 20 of shield member 12 gradually tapers outwardly as it approaches 
free edge 22, forming regions 25 of increasing thickness at diametrically 
opposed sides of shield member 12. Similar regions of increasing thickness 
(not shown) are formed on the diametrically opposed free edges of shield 
member 14. These regions of increasing thickness together assure 
continuous contact of bands 90 with the outer periphery of safety shield 
10 so as to eliminate any localized stresses which may result from point 
contact. In that regard, the thickened regions on shield members 12 and 14 
may extend along the entire width of the shield members, or may be 
confined to a relatively narrow region defining the positions for the 
assembly of bands 90. 
The present invention also contemplates forming safety shield 10 with a 
pair of apertures which are not in axial alignment. Thus, should it be 
desirable to assemble a safety shield about an elbow coupling or other 
device which angularly displaces the portions of pipe with respect to one 
another, apertures 50 and 52 may be formed with a corresponding angular 
displacement for sealing engagement thereabout. Similarly, the present 
invention contemplates forming safety shield 10 with a single aperture 50 
for assembly about a joint at an unattached end of pipe. 
As shown in the Figures, shield member 12 may include a boss member 60 
having a threaded aperture in communication with the interior of safety 
shield 10. Shield member 14 may include a similar boss member (not shown) 
having a threaded aperture communicating with the interior of safety 
shield 10. When provided in shield members 12 and 14, these threaded 
apertures provide a means for forming leak-proof connections with safety 
shield 10. 
One useful purpose for such leak-proof connections with safety shield 10 is 
to enable any liquid and/or vapor retained in the interior of safety 
shield 10 to be removed therefrom without the need for disassembling 
safety shield 10 from about the flanged pipe coupling. Thus, as shown in 
FIG. 5, a conduit 80 may be threadedly engaged with the aperture at or 
near the bottom of safety shield 10 in order to provide a means for safely 
draining any liquid which may be contained by or accumulated within safety 
shield 10. Similarly, conduit 82 may threadedly engage the aperture in 
boss member 60 at or near the top of safety shield 10 in order to safely 
evacuate any toxic or otherwise harmful vapors which may be contained by 
or accumulate in safety shield 10. Conduits 80 and 82 may direct the 
leaked fluid from safety shield 10 back into pipe P or to other locations 
as desired. 
In certain situations it may be desirable to monitor the conditions in the 
interior of safety shield 10. In those situations, additional boss members 
such as 68 and 70 having associated threaded apertures may be included to 
provide a useful means which enable various gauges or other components to 
access the interior of safety shield 10 in a leak-proof manner. FIG. 5 
shows two such gauges 84 and 86 fixedly attached to shield member 12 for 
communication with the interior of safety shield 10. Gauges 84 and 86 may 
consist of pressure gauges for measuring the pressure within safety shield 
10, temperature gauges for measuring the temperature within safety shield 
10, vacuum gauges for testing the integrity of the seal formed by safety 
shield 10, and the like. Additionally, instead of or in addition to gauges 
84 and 86, shield member 10 may have attached thereto various other 
components, such as level switches, flow switches, liquid and/or gas 
detectors, alarm systems, valves, or any other component which may be 
desirable for insuring the safety and operability of safety shield 10. Any 
number of threaded apertures communicating with the interior of the safety 
shield 10 may be employed, provided that the strength and integrity of the 
safety shield is not compromised thereby. 
In another embodiment of the present invention, the safety shield may be 
particularly adapted for providing a liquid- and vapor-tight seal about a 
valve in a piping system. A safety shield 100 in accordance with this 
embodiment of the present invention is shown in FIGS. 6-8. Typically, such 
valves include a valve body (not shown) which houses a valve seat (not 
shown) and a valve element (not shown) which is movable between a closed 
position in which the valve element mates with the valve seat to prevent 
flow of fluids through the valve body, and an open position in which the 
valve element is remote from the valve seat so that fluid may flow through 
the valve body. Such valves also typically include a valve stem 102 
operatively connected to the valve element at one end and extending 
through the valve body for connection to an operating handle 104 at the 
other end. Operation of the valve handle 104 in one rotational direction 
moves the valve element to the closed position and operation of the valve 
handle in the opposite rotational direction moves the valve element to the 
open position. 
Safety shield 100 is in all respects substantially identical to safety 
shield 10 described above. Thus, safety shield 100 includes a pair of 
shield members 12 and 14 which, in assembled position, define apertures 50 
and 52 (or, in some embodiments, only a single aperture 50) for snugly 
engaging a pipe P. A gasket assembly 40 interposed between shield members 
12 and 14 enables safety shield 100 to create a liquid-tight and 
vapor-tight enclosure in the assembled position. 
Shield member 12 includes an aperture 120 sized and shaped to snugly 
receive valve stem 102 therethrough so that valve handle 104 may be 
manipulated to operate the valve with safety shield 100 in assembled 
position thereabout. Aperture 120 includes a groove 122 in which a gasket 
124, formed from the same corrosion resistant material as gasket assembly 
40, is seated to form a liquid-tight and vapor-tight seal between valve 
stem 102 and shield member 12. This seal thus prevents fluid leakage out 
from safety shield 100 without interfering with the operation of the 
valve. 
To assemble safety shield 100 over a valve in a piping system, valve handle 
104 is initially removed from valve stem 102. Gasket members 54 and 56 are 
then assembled around pipe P on either side of the valve at appropriate 
positions so that they would be aligned with the groove 23 in free edge 
sections 22c and 22d in shield member 12 and in free edge sections 36c and 
36d in shield member 14. Gasket members 40a and 40b are then assembled to 
gasket members 54 and 56 by inserting the respective ends thereof into 
hollow projections 55 and 57. With gasket 124 in place in groove 122, 
shield member 12 is placed over the valve so that valve stem 102 protrudes 
through aperture 120. Shield member 14 may then be assembled to shield 
member 12, being careful to assure that gasket members 40a, 40b, 54 and 56 
are properly seated within groove 23. The shield members may then be held 
in this assembled position by positioning one or more bands 90 around the 
circumference of safety shield 100 and tightening threaded fastener 92 to 
compress the portions of gasket assembly 40 into sealing engagement 
between shield members 12 and 14 and between the shield members and pipe 
P. Valve handle 104 may then be reassembled to valve stem 102. Finally, 
any outlet conduits, gauges, alarms, etc. may be assembled to safety 
shield 100. 
Although the invention herein has been described with reference to 
particular embodiments, it is to be understood that these embodiments are 
merely illustrative of the principals and applications of the present 
invention. It is therefore to be understood that numerous modifications 
may be made to the illustrative embodiments and that other arrangements 
may be devised without departing from the spirit and scope of the present 
invention as set forth in the appended claims.