important that onlyq ualifiedw elders be used for this operation. Poor
welding is ac ommon cause of lining failure.
6.6.1 Polyvinyl Chloride
The maximum allowable temperature for continuous operation of type1
polyvinyl chloride (PVC) is 1408 F( 608 C). Plasticized PVC can be bonded
directly to ametal substrate. Unplasticized PVC cannot be bonded directly.It
is bondedt oaplasticizedm aterial formingad ual laminate that is then
bondedt oametal substrate.
Plasticized PVC does not have the same range of corrosion resistance as
the unplasticized PVC (type 1), Unplasticized PVC is resistant to attackb y
most acidsa nd strong alkalies as wella sg asoline, kerosene, aliphatic
alcohols, and hydrocarbons. It is subject to attackbyaromatics, chlorinated
organic com-pounds, and lacquer solvents.
In addition to handling highly corrosive and abrasive chemicals, these
liningsh ave found many applications in marinee nvironments. Table 6.18
lists the compatibility of type 1PVC with selected corrodents and Table 6.19
does the same for type 2PVC. Additional data can be found in Reference [1].
6.6.2 Chlorinated Polyvinyl Chloride
Chlorinated polyvinyl chloride (CPVC) can be continuously operated at a
maximum temperature of 200 8 F(938 C). CPVC is very similar in properties to
PVC exceptt hat it has ah igher allowable operating temperature and a
somewhat better resistance to chlorinated solvents. It is extremely difficult to
hot-weld the jointsinasheet lining. This factor should be considered when
selectingt his material.
CPVC is resistant to mosta cids,a lkalies, salts, halogens,a nd many
corrosive waters. In general, it should not be used to handle most polar
organic materials, including chlorinated or aromatic hydrocarbons, esters,
and ketones.
Table 6.20 lists the compatibility of CPVCw ith selected corrodents.
Reference [1]p rovides am ore detailed listing.
6.6.3 Polyvinylidene Fluoride
Polyvinylidenefl uoride( PVDF) mayb ec ontinuouslyo perated at a
maximum temperature of 2758 F(1358 C). It is one of the most popular lining
materials because of its range of corrosion resistance and higha llowable
operating temperature. Unless adual laminate is used, linings of PVDFwill
be loose.
PVDF is resistant to most acids,bases, and organic solvents. It also has the
ability to handle wet or dry chlorine, bromine, and other halogens.
It is not resistant to strong alkalies, fuming acids,polarsolvents, amines,
ketones, and esters. When used with strong alkalies, it stress-cracks.
Sheet Linings
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welding is ac ommon cause of lining failure.
6.6.1 Polyvinyl Chloride
The maximum allowable temperature for continuous operation of type1
polyvinyl chloride (PVC) is 1408 F( 608 C). Plasticized PVC can be bonded
directly to ametal substrate. Unplasticized PVC cannot be bonded directly.It
is bondedt oaplasticizedm aterial formingad ual laminate that is then
bondedt oametal substrate.
Plasticized PVC does not have the same range of corrosion resistance as
the unplasticized PVC (type 1), Unplasticized PVC is resistant to attackb y
most acidsa nd strong alkalies as wella sg asoline, kerosene, aliphatic
alcohols, and hydrocarbons. It is subject to attackbyaromatics, chlorinated
organic com-pounds, and lacquer solvents.
In addition to handling highly corrosive and abrasive chemicals, these
liningsh ave found many applications in marinee nvironments. Table 6.18
lists the compatibility of type 1PVC with selected corrodents and Table 6.19
does the same for type 2PVC. Additional data can be found in Reference [1].
6.6.2 Chlorinated Polyvinyl Chloride
Chlorinated polyvinyl chloride (CPVC) can be continuously operated at a
maximum temperature of 200 8 F(938 C). CPVC is very similar in properties to
PVC exceptt hat it has ah igher allowable operating temperature and a
somewhat better resistance to chlorinated solvents. It is extremely difficult to
hot-weld the jointsinasheet lining. This factor should be considered when
selectingt his material.
CPVC is resistant to mosta cids,a lkalies, salts, halogens,a nd many
corrosive waters. In general, it should not be used to handle most polar
organic materials, including chlorinated or aromatic hydrocarbons, esters,
and ketones.
Table 6.20 lists the compatibility of CPVCw ith selected corrodents.
Reference [1]p rovides am ore detailed listing.
6.6.3 Polyvinylidene Fluoride
Polyvinylidenefl uoride( PVDF) mayb ec ontinuouslyo perated at a
maximum temperature of 2758 F(1358 C). It is one of the most popular lining
materials because of its range of corrosion resistance and higha llowable
operating temperature. Unless adual laminate is used, linings of PVDFwill
be loose.
PVDF is resistant to most acids,bases, and organic solvents. It also has the
ability to handle wet or dry chlorine, bromine, and other halogens.
It is not resistant to strong alkalies, fuming acids,polarsolvents, amines,
ketones, and esters. When used with strong alkalies, it stress-cracks.
Sheet Linings
345
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