Tesco Steel & Engineering manufactures line blanks — plate devices installed between two flanges to positively turn a piping section on or off. A line blank is the family of flange-inserted isolation/spacing plates that includes the spade (paddle blind), the paddle spacer / ring spacer, and the one-piece figure-8 spectacle blind. Dimensions are made to ASME B16.48 (designed to ASME B31.3) or to customer specification. A105, SS 304/316/321, Duplex, Monel, Inconel, Hastelloy. Class 150 to 2500, PN1 to PN400. ISO 9001:2015 certified. Made in India.
Line Blanks (Spade, Spacer & Spectacle Blind)
Line blanks are core plant-isolation hardware. Tesco Steel & Engineering manufactures the complete range — spades, paddle/ring spacers, and spectacle blinds — to ASME B16.48 or drawing in the full material range. Choose the specific type below, or see the flange dimensions charts.
| Type | Bore | Function |
|---|---|---|
| Spade (Paddle Blind) | Solid (no bore) | Blanks / isolates the line — the “off” position |
| Paddle Spacer | Open bore + handle | Keeps the line open — the “on” position (pairs with a spade) |
| Ring Spacer | Open bore (no handle) | Open-position spacer without a tab |
| Spectacle Blind | One solid + one open, joined by a web | Figure-8 part flipped to isolate or open |
Spectacle blinds are used on smaller lines (one part, flip to change); spade & spacer pairs are used on larger lines where a one-piece spectacle blind would be too heavy. A bleed ring / drip ring is a related open-bore spacer with a tapped vent/drain.
| Line Blanks are available in the following specifications: | |
|---|---|
| Size | 1/2"NB to 56"NB |
| Class | 150#, 300#, 3000#, 6000#, 9000# |
| Sch (Schedule) | XS, XXS, STD & Schedule 20, 40, 80, 160 |
| Pressure Ratings | PN 1 - PN 400 |
| Stainless Steel Line Blanks | ASTM A 182 F - 304 / 304H / 304L / 316 / 316H / 316L / 316Ti, 309, 310, 317L, 321, 347, 904L |
| Duplex Steel Line Blanks | ASTM A 182 - F 51, F 53, F 55 |
| Alloy Steel Line Blanks | ASTM A 182 - F5, F9, F11, F21, F22 & F91 |
| Carbon Steel Line Blanks | ASTM A 105 |
| Low Temp. Carbon Steel Line Blanks (LTCS Orifice Flanges Flanges) | A 350 LF2 |
| Copper Nickel (Cu-Ni) Line Blanks | C70600, 90/10, C71500, 70/30, C71640 |
| Nickel Line Blanks | UNS N02200, UNS N02201 |
| Monel Line Blanks | UNS N04400, UNS N05500, Alloy 20 |
| Inconel Line Blanks | UNS N06600, UNS N06601, UNS N06625, UNS N08800, UNS N08810, UNS N08825 |
| Hastelloy Line Blanks | UNS N10276, UNS N06022, UNS N10665, UNS N06455 |
| Titanium Line Blanks | Gr. 1, Gr. 2, Gr. 3, DTH 3.7035, DTH 3.7055 |
| Other Services | Hot Dip Galvanized (GI) Line Blanks Sand Blasting on Line Blanks Shot Peening on Line Blanks Epoxy Coating on Line Blanks FBE Coating on Line Blanks |
A solid metal plate gives guaranteed, fail-safe isolation for maintenance, vessel entry, and tie-ins — no valve seat to leak.
Spades, paddle & ring spacers, and spectacle blinds — the whole line-blank family from one maker, correctly matched.
Dimensioned to ASME B16.48 and designed to ASME B31.3 for the full Class 150–2500 range, RF or RTJ.
A105, LTCS, SS 304/316/321, Duplex, Monel, Inconel, Hastelloy, Copper-Nickel, and Titanium.
Handles stamped with size, rating, and material for clear identification and safe blind-list control.
Manufactured to ASME B16.48 or your drawing, certified with EN 10204 3.1 MTC.
| Material | Properties | Typical Use |
|---|---|---|
| A105 Carbon Steel / A350 LF2 (LTCS) | Strong, economical; LF2 for low temp | Non-corrosive & low-temperature lines |
| SS 304 / 316 / 321 | Good corrosion resistance; 321 high-temp | Process, chemical & high-temperature lines |
| Duplex 2205 / Super Duplex 2507 | High strength & chloride resistance | Seawater & offshore isolation |
| Monel 400 / Inconel | Excellent in HF, marine & high-temp | HF, seawater & high-temperature lines |
| Hastelloy / Copper-Nickel / Titanium | Superior corrosion resistance | Aggressive chemical & marine service |
| Industry | Typical Use | Why Line Blank |
|---|---|---|
| Oil & Gas | Maintenance isolation & tie-ins | Positive, fail-safe blanking |
| Refinery & Petrochemical | Turnaround line isolation | Safe vessel entry; full material range |
| Power Generation | Boiler & steam-line isolation | SS 321 high-temperature service |
| Chemical Plants | Corrosive-line isolation | Monel / Inconel / Hastelloy |
| Pipelines | Section isolation & testing | High-class positive isolation |
| Pharmaceutical / Process | Equipment isolation | Clean SS plates; clear marking |
| Offshore & Marine | Topside line isolation | Duplex / alloy corrosion resistance |
| Water & Utilities | Maintenance blanking | Economical positive isolation |
Q1. What is a line blank?
A line blank is a plate device fitted between two pipe flanges to positively turn a line on or off. It is the general term for the family of flange-inserted plates — spades (paddle blinds), paddle/ring spacers, and spectacle blinds — that provide guaranteed, fail-safe isolation or full-bore flow, dimensioned to ASME B16.48.
Q2. What are the types of line blank?
A spade (paddle blind) is solid and blanks the line (off); a paddle spacer or ring spacer has an open bore and keeps the line open (on); and a spectacle blind joins a solid disc and an open ring in one figure-8 part that is flipped to isolate or open. Spades and spacers are used on larger lines; spectacle blinds on smaller lines.
Q3. Why use a line blank instead of a valve?
A valve can pass or leak across its seat, so it is not positive isolation for entry or hot work. A line blank is a continuous solid metal plate across the bore, giving a guaranteed, visible, fail-safe barrier. Safety procedures for vessel entry and maintenance therefore require line blanks rather than relying on a closed valve.
Q4. What standard covers line blanks?
ASME B16.48 is the standard for line blanks (spades, spacers, and the discs/rings of spectacle blinds) for Class 150 to 2500, dimensioned to the matching ASME B16.5 flange, and they are designed to the ASME B31.3 process-piping code. They can also be made to customer specification.
Q5. What is the difference between a spade-and-spacer set and a spectacle blind?
A spectacle blind joins a solid disc and an open ring with a web into one part — you flip it to isolate or open. A spade and spacer do the same job as two separate plates, used on larger lines where a one-piece spectacle blind would be too heavy to handle. Function is the same; the difference is one-piece vs two-piece.
Q6. How thick should a line blank be?
The solid plate (spade or spectacle-blind disc) must withstand the full line pressure acting across the open bore without excessive deflection, so thickness increases with size and pressure class. We calculate and supply line blanks to the correct ASME B16.48 thickness for the class and size.
Q7. What materials are line blanks made from?
Carbon steel (A105) and LTCS (A350 LF2), stainless steels (304/316/321), Duplex (F51/F53/F55), Monel, Inconel, Hastelloy, Copper-Nickel, and Titanium — matched to the line material, fluid, and temperature.
Q8. Can line blanks be supplied to our drawing and certified?
Yes. We supply the full line-blank range — spades, paddle/ring spacers, and spectacle blinds — to ASME B16.48 or your drawing, with size, class, facing, material, and handle marking, and EN 10204 3.1 material test certificates on request. Send your line details for a quote.