Line Blank Dimensions & Tolerances
ASME B16.48 Standard Flanges: Dimensions | Specifications | Material Grade | Standards | About ANSI B16.48 | All Product Types
ASME B16.48 is a key standard issued by the American Society of Mechanical Engineers that governs the design, dimensions, tolerances, and pressure class ratings of line blanks, including spades, spacers, and spectacle blinds used in piping systems. This standard ensures proper isolation, flow control, and safe shutdown capability in critical process lines.
The B16.48 standard provides detailed guidance on flange thicknesses, outer diameters, handle dimensions, gasket contact surfaces, and tolerances to ensure compatibility with ASME B16.5 and B16.47 flanges. It covers nominal pipe sizes (NPS) from ½″ to 24″ and pressure ratings of Class 150, 300, 600, and 900.
Unlike typical pressure-retaining flanges, line blanks per ASME B16.48 are not bolted components themselves but rather designed to be sandwiched between two flanges for system isolation or maintenance. They are widely used in industries like oil and gas, refineries, petrochemical plants, and offshore piping systems.
This standard also mandates identification markings for size, rating, material, and heat number, and defines surface finish requirements such as stock finish or serrated finish, depending on sealing performance needs. ASME B16.48 is essential for ensuring dimensional interchangeability, safe operation under pressure, and standardized fabrication of line blank components across global piping networks.
For complete technical details, including dimensions, pressure rating classes, weight charts, sizes, tolerances, and material specifications of our ANSI B16.48 Standard Flanges, please download the full Catalog PDF below.
Specification | Details |
---|---|
Standard | ASME B16.48 – Line Blanks (Spades, Spacers, Spectacle Blinds) |
Size Range | ½″ to 24″ NPS (DN15 to DN600) |
Pressure Ratings | Class 150, 300, 600, 900 |
Type of Blanks | Spectacle Blind, Paddle Blank (Spade), Paddle Spacer |
Face Types | Raised Face (RF), Flat Face (FF), Ring Type Joint (RTJ) – if applicable |
Facing Finish | Stock Finish (125–250 AARH), Serrated Finish, Smooth Finish |
Thickness Tolerance | ±0.25 mm (as per ASME B16.48 standard requirements) |
Material Compatibility | To match the companion flanges per B16.5 / B16.47 materials |
Marking Requirements | Marked with NPS, Class, Material Grade, Heat Number, Manufacturer’s ID |
Interchangeability | Designed for compatibility with ASME B16.5 and B16.47 flanges |
Applications | Flow isolation, line maintenance, system shutdown, safety blocking |
Documentation | EN 10204 3.1 / 3.2, NACE MR0175, ISO 9001, PED 2014/68/EU |
Application Industries | Oil & Gas, Petrochemical, Power Generation, Water Treatment, Food & Beverage, Fire Protection Systems, Pulp & Paper, Shipbuilding, HVAC, Offshore |
Origin | Made in India (by Nutech Overseas) |
Export Network | USA, Europe, and Middle East |
Material Category | B16.48 Flange Grades |
---|---|
Stainless Steel B16.48 Flange | ASTM A182 F304 / F304L / F304H, F316 / F316L / F316Ti, F310, F309S, F317 / F317L, F321 / F321H, F347 / F347H, F904L, ASTM A351 CF3 / CF3M / CF8 / CF8M / CF8C, DIN 1.4301, 1.4306, 1.4307, 1.4311, 1.4401, 1.4404, 1.4408, 1.4409, 1.4541, 1.4571, 1.4550, 1.4435, 1.4539 |
Duplex Steel B16.48 Flange | ASTM A182 F51 / F52 / F53 / F54 / F55 / F57 / F59 / F60 / F61, UNS S31803 / S32205 |
Super Duplex Steel B16.48 Flange | ASTM A182 F53 / F55 / F57 / F59 / F60 / F61, UNS S32750 / S32760 |
Carbon Steel B16.48 Flange | ASTM A105 / A105N, ASTM A350 LF2, ASTM A694 F52 / F56 / F60 / F65 / F70 / F80, ASTM A216 WCB, DIN 1.0460 / 1.0402 / 1.0619, Die Steel, Mild Steel |
Alloy Steel B16.48 Flange | ASTM A182 F5 / F9 / F11 / F12 / F22 / F91, AISI 4130 / 4140 |
Nickel Alloy B16.48 Flange | Nickel 200 / 201, ASTM B564 |
Monel B16.48 Flange | Monel 400 (UNS N04400), Monel K500 (UNS N05500), ASTM B564 |
Inconel B16.48 Flange | Inconel 600 / 601 / 625 / 690 / 718 / 783 / X750, ASTM B564 |
Incoloy B16.48 Flange | Incoloy 800 / 800H / 800HT (UNS N08800), Incoloy 825 (UNS N08825), Incoloy 925, ASTM B564 |
Hastelloy B16.48 Flange | Hastelloy C276 (UNS N10276), C22 (UNS N06022), C4, C2000, B2, B3, X, ASTM B564 |
Alloy 20 B16.48 Flange | Alloy 20 / 20Cb-3, Carpenter® 20, ASTM B462 |
254 SMO B16.48 Flange | SMO 254 / 6Mo, UNS S31254, DIN 1.4547, ASTM A182 |
Copper Nickel B16.48 Flange | Copper Nickel 90/10 (C70600), 70/30 (C71500), UNS C71640, ASTM B61 / B62 / B151 / B152 |
Copper B16.48 Flange | TP1, TP2, T1, T2, C10100–C12300, C14200–C17200, C21000–C71520, including C10930, C11000, C11400, C12000, C12200, C26000, C28000, C33000, C44300, C70600, etc. |
Brass B16.48 Flange | Grades 3602, 2604, H59, H62, etc. |
Aluminium B16.48 Flange | Aluminium Grades 5052, 6061, 6063, 2017, 7075, etc. |
Titanium B16.48 Flange | ASTM B381 Gr.1 / Gr.2 / Gr.4 / Gr.5 / Gr.7, UNS R50250 / R50400 / R50550 / R50700 / R52400 / R53400 / R56320 / R56400 |
Other Special Grades | Al6XN, Tin Bronze, Aluminium Bronze, Lead Bronze, Nimonic 75 / 80A / 90 |
ASME B16.48 is a standard developed by the American Society of Mechanical Engineers that covers the design, dimensions, tolerances, and marking requirements for line blanks such as spectacle blinds, paddle blanks (spades), and paddle spacers. These components are not used to join two pipes, but rather to block or isolate flow in a pipeline, particularly during maintenance or inspection.
They are commonly installed between two ASME B16.5 or B16.47 flanges and are used in critical piping systems found in:
Line blanks per B16.48 are essential for ensuring safe shutdowns, preventing backflow, and maintaining process integrity.
ASME B16.48 provides specific tolerances for the dimensions of line blanks to ensure proper fit and safe installation. These tolerances help maintain gasket alignment, bolt hole compatibility, and system pressure integrity.
Key dimensional tolerances include:
These tolerances are critical in high-pressure and high-temperature systems where precision is essential to avoid leaks or flange damage.
While both ASME B16.48 and B16.5 are essential flange-related standards, they serve different functions in a piping system:
Feature | ASME B16.48 | ASME B16.5 |
---|---|---|
Purpose | Line blanks (spades, spacers, spectacle blinds) for flow isolation | Pressure-retaining flanges for connecting pipes, valves, equipment |
Component Type | Non-pressure retaining components | Pressure-retaining flange components |
Size Range | ½″ to 24″ NPS | ½″ to 24″ NPS |
Pressure Classes | Class 150, 300, 600, 900 | Class 150, 300, 600, 900, 1500, 2500 |
Use Cases | Isolation, shutdown, maintenance operations | Permanent pipe-to-pipe or pipe-to-equipment connections |
Facing Finish | Stock, serrated, smooth | Stock, serrated, smooth (based on flange type) |
In summary, ASME B16.48 is used for temporary flow control and safety, whereas ASME B16.5 is used for permanent flange connections in piping systems.
Proper installation of ASME B16.48 spectacle blinds, spades, and spacers is essential to ensure pressure integrity and operational safety. These components are typically installed between flanges in critical isolation points of a pipeline system.
Key installation guidelines include:
These precautions help maintain seal integrity, prevent leaks, and extend the lifespan of isolation components under high-pressure service conditions.
Material selection for ASME B16.48 line blanks — including spectacle blinds, spades, and spacers — is crucial for ensuring long-term performance, corrosion resistance, and compliance with project specifications. The right material depends on several technical factors:
Key Considerations:
By selecting the appropriate material, end users can avoid failures due to corrosion, erosion, or thermal stress — ensuring compliance with international standards and increasing system longevity.
Yes, Nutech is a trusted manufacturer and exporter of ASME B16.48 line blanks, including spectacle blinds, spades, and spacers, to a wide range of global markets. We serve various industries such as oil & gas, power generation, marine, and petrochemical sectors with timely delivery and customized specifications.
We regularly export to key regions including:
Our export-grade flange blanks conform to ASME, EN, and PED standards, and are supplied with complete test certifications, inspection reports, and traceability. With strong logistics and compliance experience, we ensure reliable global support for EPC projects, OEMs, and end users.