The Equipment Design Process
355
that the insulation can be properly sealed without hindering valve
operation.
7. Tank design:
The design of roof insulations presents special problems due to
wind and the flexing of the roof. The insulation must be secured to
the roof either by pinning, cabling, or adhesion.
It is very difficult to design and maintain a dry roof insulation
system. The sealants around the nozzles and other projections have
finite lives, and the possibility of puncture due to foot traffic or leaks
caused by roof flexing is very high. Insulation that does not absorb
water is preferred, and there should be a definite separation between
the wall and roof insulation. An angle with an outstanding leg is
required to provide the separation.
The radial loads that can be withstood by ¾-in. banding are small
for large-diameter equipment. To have an adequate system, the use
of this size band requires that the bands be anchored at frequent
intervals. It may be cost effective to use welded pins to impale the
insulation. Where pins are not permitted by code, a proprietary
system using wider bands or rib-type attachments should be considered. More recently developed prefabricated insulation systems
should be investigated. However, system selection may be necessary
prior to the final design of the tank or vessel so that adequate supports can be provided.
The bottom 12 in. of tank wall insulation should be nonwicking to
prevent moisture being drawn up into the insulation. Locations with
high probability of high water in the tank dike may require up to 48
in. of nonwicking insulation. Cellular glass is the preferred material
for this bottom section of insulation on the tank.
For further details and design plates, refer to the Commercial and Industrial
Insulation Standards published by Midwest Insulation Contractors Association
(MICA) at 2202 Hanscom Blvd., Omaha, NE 68105.
11.3.3 industries and Systems Covered
In this section the materials and methods generally used in the following
representative industries and systems are discussed: chemical, petroleum
refinery, water treatment and supply systems, gas industry, pipeline industry, marine industry, telephone industry, nuclear power industry, and aerospace industry.
The basic design techniques used by the various industries will fall into
one of the following categories:
355
that the insulation can be properly sealed without hindering valve
operation.
7. Tank design:
The design of roof insulations presents special problems due to
wind and the flexing of the roof. The insulation must be secured to
the roof either by pinning, cabling, or adhesion.
It is very difficult to design and maintain a dry roof insulation
system. The sealants around the nozzles and other projections have
finite lives, and the possibility of puncture due to foot traffic or leaks
caused by roof flexing is very high. Insulation that does not absorb
water is preferred, and there should be a definite separation between
the wall and roof insulation. An angle with an outstanding leg is
required to provide the separation.
The radial loads that can be withstood by ¾-in. banding are small
for large-diameter equipment. To have an adequate system, the use
of this size band requires that the bands be anchored at frequent
intervals. It may be cost effective to use welded pins to impale the
insulation. Where pins are not permitted by code, a proprietary
system using wider bands or rib-type attachments should be considered. More recently developed prefabricated insulation systems
should be investigated. However, system selection may be necessary
prior to the final design of the tank or vessel so that adequate supports can be provided.
The bottom 12 in. of tank wall insulation should be nonwicking to
prevent moisture being drawn up into the insulation. Locations with
high probability of high water in the tank dike may require up to 48
in. of nonwicking insulation. Cellular glass is the preferred material
for this bottom section of insulation on the tank.
For further details and design plates, refer to the Commercial and Industrial
Insulation Standards published by Midwest Insulation Contractors Association
(MICA) at 2202 Hanscom Blvd., Omaha, NE 68105.
11.3.3 industries and Systems Covered
In this section the materials and methods generally used in the following
representative industries and systems are discussed: chemical, petroleum
refinery, water treatment and supply systems, gas industry, pipeline industry, marine industry, telephone industry, nuclear power industry, and aerospace industry.
The basic design techniques used by the various industries will fall into
one of the following categories: