INSULATION OF VESSELS
Note to Specifications
Under the general heading 'vessel' can be included small and large rectangular, cylindrical and irregular pieces of equipment, high towers for chemical process plants, large storage tanks and spheres as well as boilers and steam turbines. Because of the complexity of this equipment it is not possible to provide model specifications to meet all
requirements. However, there are certain basic principles which must be observed, and the following will provide the necessary information to assist in drawing up detailed specifications for using
Owens Corning South Africa Rockwool products for the insulation of this type of equipment. In selecting the most suitable product the following criteria must be considered:
- Maximum service temperature
- Degree of insulation efficiency required
- Robustness of insulation to support the applied finish and withstand the environment.
Generally the higher the temperature the higher the density required, but it may be prudent to select a density of slab higher than that which is necessary for the temperature where a more robust insulant is requ ired to support the covering at times be imposed, e.g. on tops of large tanks.
Cylindrical Vessels Model Specifications
Application of lnsulboard
Cylindrical vessels shall be insulated with Owens Corning South Africa lnsulboard, firmly secured to the vessel with metal bands adhesive
or a combination of both. The metal bands should not be overtensioned so
as to significantly reduce the thickness of the insulation. On vertical
surfaces circumferential support rings shall be fitted and spaced apart at
distances which will provide adequate support according to the weight of
the insulation. The support rings shall protrude from the vessel to a
maximum distance of 10 mm less than the thickness of insulation. All
joints must be well butted together and vertical joints on adjacent
courses staggered. In multi-layer applications all joints shall be
staggered. The insulation may be fixed to domed ends by impaling over pins
and Vessel to be insulated with Owens Corning South Africa lnsulmatt type ... thickness
... mm. Metal pins or forked studs to be welded/screwed to the surface of
the vessel at the following pitches: on vertical surfaces at an
approximate square pitch of 450 mm, upward facing surfaces 600 mm,
overhanging or downward facing surfaces 300 mm. When using pins with
spring clip washers the length of the pin to be 12 mm shorter than the
thickness of the insulation to avoid hot spots on the cladding. Forked
studs to be longer than the pins welded to the vessel. In either case the
outer end of the pins should transmitted direct to the covering.
Application of lnsulmatt
Vessel to be insulated with Owens Corning South Africa Insulmatt.
type...thickness...mm. Metal pins or forked studs to be welded/screwed to
the surface of the vessel at the following pitches:
on vertical surfaces at an approximate square pitch of 450 mm, upward
facing surface 600mm, overhanging or downward facing surfaces 600 mm,
overhanging or downward facing surfaces 300 mm. When using pins with
spring clip washers the length of the pin to be 12 mm shorter than the
thickness of the insulation to avoid hot spots on the cladding. Forked
studs to be longer than the insulation thickness. The mattress to be
impaled over the pins, secured with 50 mm flat square washers and capped
with spring clip washers. Forked studs should be turned back and recesses into the insulation by
approximately 10 mm. Mattresses to edges of the outer layer of wire
netting laced together with wire. Joints of multi-layer insulation should
be staggered.
Sheet metal cladding - for internal or external use
The application of sheet metal cladding must meet certain requirements
which are set out below but, depending on size, location, environment,
etc., a specific design may be necessary. Special types of studs which
reduce heat conduction m ay have to be provided, welded to the vessel
surface or other attachments used. Alternatively a self sup- porting
framework may be installed. Flat or profiled sheet may be used. All
circumferential joints must be overlapped weatherwise in order to shed
water, and secured with self-tapping screws or easy-fix rivets. Where
necessary joints should be sealed with a suitable sealant to prevent the
ingress of water or other contaminating fluids. On large vessels certain
overlaps should be designed to provide for expansion.
Rectangular Vessels, Tanks, or Flat Surfaces
Application of lnsulboard
Any density of lnsulboard can be used in such applications, actual choice
depending on performance required. To be insulated with Owens Corning South Africa
lnsulboard type ... thickness ... mm
secured to the surface to be insulated with suitable adhesive. The
adhesive to be applied to cover the entire surface. (It is important to follow the manufacturer's instructions.) Alternatively the insulation may be impaled over pins fixed to the
surface of the vessel at the following pitches: on vertical surfaces at an
approximate square pitch of 450 mm, on upward facing surfaces at
approximately 600 mm and overhanging or downward facing surfaces 300 mm.
Location of pins should be arranged so that there is a pin not more than
50 mm from each corner of each slab. All joints should be closely butted
together.
Vertical joints (and in multi-layer applications all joints) must be
staggered and, at corners, adjacent slabs must be overlapped to the
thickness of the insulation. When using pins with spring clip washers, the
length of the pin should be 10 mm less than the thickness of the
insulation to avoid hot spots on the cladding.
Application of lnsulmatt
Vessel to be insulated with Owens Corning South Africa lnsulmatt type ... thickness ...
mm. Metal pins or forked studs to be welded/ screwed to the surface of the
vessel at the following pitches: on vertical surfaces at an approximate
square pitch of 450 mm, upward facing surfaces 600 mm, overhanging or
downward facing surfaces 300 mm. When using pins with spring clip washers
the length of the pin should be 10 mm less than the thickness of the
insulation to avoid hot spots on the cladding. Forked studs to be longer
than the insulation thickness. The mattresses to be impaled over the pins,
secured with 50 mm flat square washers and capped with spring clip
washers. Forked studs should be turned back and recessed into the
insulation approximately 10 mm. Mattresses to be closely butted together
and the edges of the outer layer of wire netting laced together with wire.
Joints of multi-layer insulation should be staggered. Care must be taken
to maintain insulation thickness around the corners.
Sheet Metal Cladding
The application of sheet metal cladding must meet certain requirements
which are set out below but a specific design may be necessary depending
on size, location, environment, etc. Special types of studs which reduce
heat conduction may have to be provided, welded to the vessels surface or
other attachments used. Alternatively a self-supporting framework may be
installed. Flat or profiled sheet may be used. All circumferential joints must be overlapped in order to shed water, and
secured with self-tapping screws or easy-fix rivets. Where necessary
joints should be sealed with a suitable sealant to prevent the ingress of
water or other contaminating fluids. On large vessels certain overlaps
should be designed to provide for expansion.
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