THE DOW CHEMICAL COMPANY ENGINEERING SPECIFICATION MATERIALS G8S-8005-09 GLOBAL 05-OCT-2014 Page 1 of 14 DOW RESTRICTED Line Blank Specification 1.0 Purpose 1.1 This document provides specifications for line blanks (a.k.a. slip blanks, pancakes, paddle blanks) NPS 1/2 through NPS 24 up through Class 1500 and NPS 1/2 through NPS 12 up through Class 2500 designed as positive shut-off devices in ASME B16.5 raised face metal flanges and plastic lined pipe flanges. These line blanks may be used. 1.1.1 To seal off part of a process permanently. 1.1.2 To prevent accidental flow through a pipeline or into a vessel when installed adjacent to, or in conjunction with, a valve during temporary maintenance activity. 1.1.3 As isolation for hydrostatic or pneumatic testing. 1.2 Line blanks for ring type joint (RTJ) flanges are not covered in this document. Refer to ASME B16.48 to specify RTJ line blanks. 1.3 Line blanks for flat face flanges constructed of gray cast iron, FRP, or thermoplastic shall be full face dimensions with full face gaskets. Thicknesses can still be based on this document. 1.4 If line blanks are needed for flanged connections greater than NPS 24”, for custom PCE body flanges, or for other non-standard flanges, contact the PCE Discipline TRN. 2.0 To Seal Off Part of a Process Permanently: 2.1 Line blanks according to “ASME B16.48 Line Blanks” are acceptable for raised face flanges. Flat face flanges require full face line blanks. 2.2 ASME B16.48 line blanks meet the full temperature-pressure ratings based on materials of construction according to ASME B16.5 Table 1-A. 2.2.1 Metal liners which match the material of construction of the piping can be used on the process side of a carbon steel line blank. Metal liner thickness must be verified with calculations if in vacuum service. 2.2.2 Pressure-temperature ratings for carbon steel must be used if a metal liner option is used. 2.3 For reference, required line blank thicknesses according to ASME B16.48 are given in Table 1. Line blanks inserted between components with different pressure ratings shall be selected based on the higher pressure rating. 2.4 Specified gaskets from the CPPS shall be used with line blanks.
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THE DOW CHEMICAL COMPANY ENGINEERING SPECIFICATION
MATERIALS G8S-8005-09
GLOBAL 05-OCT-2014
Page 1 of 14
DOW RESTRICTED
Line Blank Specification
1.0 Purpose
1.1 This document provides specifications for line blanks (a.k.a. slip blanks, pancakes, paddle
blanks) NPS 1/2 through NPS 24 up through Class 1500 and NPS 1/2 through NPS 12 up
through Class 2500 designed as positive shut-off devices in ASME B16.5 raised face metal
flanges and plastic lined pipe flanges. These line blanks may be used.
1.1.1 To seal off part of a process permanently.
1.1.2 To prevent accidental flow through a pipeline or into a vessel when installed
adjacent to, or in conjunction with, a valve during temporary maintenance activity.
1.1.3 As isolation for hydrostatic or pneumatic testing.
1.2 Line blanks for ring type joint (RTJ) flanges are not covered in this document. Refer to ASME
B16.48 to specify RTJ line blanks.
1.3 Line blanks for flat face flanges constructed of gray cast iron, FRP, or thermoplastic shall be
full face dimensions with full face gaskets. Thicknesses can still be based on this document.
1.4 If line blanks are needed for flanged connections greater than NPS 24”, for custom PCE body
flanges, or for other non-standard flanges, contact the PCE Discipline TRN.
2.0 To Seal Off Part of a Process Permanently:
2.1 Line blanks according to “ASME B16.48 Line Blanks” are acceptable for raised face flanges.
Flat face flanges require full face line blanks.
2.2 ASME B16.48 line blanks meet the full temperature-pressure ratings based on materials of
construction according to ASME B16.5 Table 1-A.
2.2.1 Metal liners which match the material of construction of the piping can be used on
the process side of a carbon steel line blank. Metal liner thickness must be verified
with calculations if in vacuum service.
2.2.2 Pressure-temperature ratings for carbon steel must be used if a metal liner option
is used.
2.3 For reference, required line blank thicknesses according to ASME B16.48 are given in Table
1. Line blanks inserted between components with different pressure ratings shall be selected
based on the higher pressure rating.
2.4 Specified gaskets from the CPPS shall be used with line blanks.
THE DOW CHEMICAL COMPANY ENGINEERING SPECIFICATION
MATERIALS G8S-8005-09
GLOBAL 05-OCT-2014
Page 2 of 14
DOW RESTRICTED
3.0 For Temporary (Monitored) Maintenance/Construction Activities:
3.1 Line blanks according to, “ASME B16.48 Line Blanks” can be used. See Table 1 for required
thicknesses.
3.2 Table 2 or Table 3 may be used to determine if thinner, non-standard line blanks are allowed
based on the maximum possible pressure in the system being isolated. The pressure rating
listed in Table 2 and Table 3 is for temperature up to 300F (149C); the rating listed shall be
multiplied by the derating factor tabulated in Table 8 if the temperature exceeds the basis for
Table 2 or Table 3.
3.3 Maximum pressure shall be the highest pressure listed in the CPPS heading or determined
by Process Engineering/Site Piping TR.
3.4 Table 2 or Table 3 thickness blanks shall be removed when construction has been approved
for commissioning.
3.5 The thicknesses listed in Table 2 or Table 3 may be used for non-standard line blanks
fabricated from A516 Grade 70, A105, A240 Grade 304/304L or 316/316L.
3.5.1 If other solid alloy line blanks are used, thickness must be verified by calculations.
3.5.2 The 1/8” thickness can be used as a “vapor blank” for applications where there is
NO differential pressure (i.e., air gapped, open ended) but a physical barrier is still
needed to prevent vapors/fumes from backing up into a piece of equipment.
3.5.3 Dimensions for non-standard line blanks are shown in Figure 1 and in the
applicable pressure class table:
3.5.3.1 Table 4: Class 150, 300, and 600 English Dimensions
3.5.3.2 Table 5: Class 900, 1500, and 2500 English Dimensions
3.5.3.3 Table 6: Class 150, 300, and 600 Metric Dimensions
3.5.3.4 Table 7: Class 900, 1500, and 2500 Metric Dimensions
3.5.4 A gasket phonographic surface finish is not required for non-standard line blanks.
THE DOW CHEMICAL COMPANY ENGINEERING SPECIFICATION
MATERIALS G8S-8005-09
GLOBAL 05-OCT-2014
Page 3 of 14
DOW RESTRICTED
3.6 If carbon steel and stainless steel materials (see Para. 3.2.1) are not compatible with the
process:
3.6.1 A 1/8” alloy blind disc compatible with the process may be used on the process
side of a line blank. Alloy blind disc thickness must be verified with calculations if