Chat With Us

Spectacle Blind Flange

Spectacle Blind Flange

Get In Touch

Request Quote WhatsApp Us Call Now

Spectacle Blind Flange Manufacturer & Supplier in Mumbai

Nishra Overseas manufactures and supplies Spectacle Blind Flange in Mumbai for industrial piping systems requiring positive line isolation and controlled flow-path operation. Also known as a spectacle blind, spectacle blind flange, or figure-8 blank, this component consists of one solid blind section and one open spacer section connected by a web. The assembly is installed between mating pipe flanges and can be repositioned to either block the line or allow flow without removing the complete component from the piping system. ASME B16.48 specifically defines a figure-8 blank, also called a spectacle blank, as a pressure-retaining plate with one solid end and one open end connected by a web or tie bar.

Spectacle blinds are selected for process piping, maintenance isolation, shutdown work, refinery systems, petrochemical plants, chemical processing and other applications where a visible and mechanically positive method of line isolation is required. They can be manufactured from suitable carbon steel, stainless steel, alloy steel, duplex and other specified materials according to the service conditions and project requirements. Nishra Overseas is an ISO 9001:2015 certified manufacturer, stockist and exporter with more than 25 years of industry experience.

Spectacle Blind Flange Manufacturer in Mumbai

As a Spectacle Blind Flange Manufacturer in Mumbai, Nishra Overseas supplies figure-8 line blanks according to applicable dimensional standards, material specifications and customer requirements. Manufacturing starts with verified raw material selected according to the required grade and service conditions.

The blank and spacer sections of a spectacle blind are designed as an integrated line-blank component. Manufacturing may involve suitable plate or forged material preparation, profile cutting/forming, machining, dimensional finishing, facing and inspection. Where required by the material specification, heat treatment is performed according to the applicable requirements.

Critical manufacturing and inspection activities can include:

  • Raw material identification and verification

  • Plate or forged material preparation

  • Figure-8 profile forming or machining

  • Blind and spacer dimensional control

  • Bore and outside-diameter machining

  • Web/tie-bar dimensional verification

  • Flange-facing compatibility

  • Surface finishing

  • Marking and traceability

  • Final dimensional inspection

The solid section provides line blocking when positioned between the mating flanges, while the open spacer section maintains the flow path when the line is in service. Correct dimensional compatibility with the surrounding flange assembly is therefore essential.

Spectacle Blind Flange Supplier in Mumbai

Nishra Overseas is a Spectacle Blind Flange Supplier in Mumbai serving EPC contractors, fabricators, OEMs, engineering consultants, procurement teams and industrial maintenance buyers.

Supply can be arranged according to the required nominal pipe size, pressure class, material grade, facing arrangement, applicable standard, quantity and inspection requirements. Project buyers can provide drawings, piping class specifications or datasheets so the line blank configuration can be matched with the intended flange assembly.

For industrial procurement, documentation such as Mill Test Certificates, material traceability, PMI and third-party inspection can be supported where specified by the purchase order or project requirements.

Spectacle Blind Flange Exporter in Mumbai

Nishra Overseas also supplies industrial piping products internationally as a Spectacle Blind Flange Exporter in Mumbai. The company states that it exports its product range to more than 50 countries across the USA, Europe, Middle East, Asia and Australia.

Export orders can be supplied with applicable material certificates, inspection documentation, traceability information and export packaging according to project requirements. Shipping arrangements and documentation are finalized according to the destination and purchase order.

Spectacle Blind Flange Specifications

The specification of a spectacle blind depends on the applicable line-blank standard, pressure class, nominal size, facing and material requirement.

Parameter Specification / Availability
Product Spectacle Blind Flange / Figure-8 Blank
Standard ASME B16.48 or applicable project standard
Material Carbon Steel, Stainless Steel, Alloy Steel, Duplex and specified alloys
Type Figure-8 / Spectacle Blind
Configuration Solid Blind + Open Spacer
Size As specified by project requirement
Pressure Class 150, 300, 600, 900, 1500, 2500 where applicable
Facing Raised Face, Ring Type Joint or applicable configuration
Manufacturing Machined / formed / forged as applicable
Thickness According to applicable standard and pressure class
Bore / ID According to required nominal size
Surface Finish As specified
Heat Treatment As required by material specification
Marking According to applicable standard
Inspection As specified in purchase order/project specification
Documentation MTC and inspection documentation where required

ASME B16.48 covers operating line blanks, including figure-8 blanks, within its specified size and pressure-class range and addresses pressure-temperature ratings, materials, dimensions, tolerances, marking and testing.

Exact dimensions should always be confirmed against the applicable standard and project specification rather than using dimensions from a conventional blind flange.

Features of Spectacle Blind Flange

Key technical characteristics of spectacle blind line blanks include:

  • Combines a solid blind and open spacer in one assembly

  • Provides positive mechanical line isolation

  • Allows switching between open and blocked positions

  • Figure-8 configuration provides clear visual identification

  • Designed for installation between mating pipe flanges

  • Available in multiple pressure classes

  • Suitable for different material grades

  • Available with specified flange-facing configurations

  • Supports controlled maintenance isolation

  • Can be supplied with material traceability

  • Suitable for project-specific inspection requirements

  • Designed according to applicable line-blank dimensions

The primary functional advantage is the ability to establish either a flow-through or blocked condition using the same integrated component, subject to the approved plant isolation procedure.

Applications of Spectacle Blind Flange

Spectacle blinds are primarily used for positive isolation of piping systems during maintenance, inspection, testing, shutdown and plant modification activities. The solid portion blocks the line when correctly positioned, while the spacer portion provides an open flow path when required.

Typical applications include:

  • Refinery process piping

  • Oil and gas facilities

  • Petrochemical plants

  • Chemical processing systems

  • Power plants

  • Process utilities

  • Pipeline isolation points

  • Plant maintenance systems

  • Shutdown and turnaround activities

  • Equipment isolation arrangements

  • Industrial process piping

For critical isolation, installation and repositioning should always follow the facility's approved operating, isolation and safety procedures.

Industries We Serve

Nishra Overseas supplies spectacle blind line blanks for procurement and project requirements across:

  • Oil & Gas

  • Refineries

  • Petrochemical

  • Chemical Processing

  • Power Generation

  • Marine and Offshore

  • Water and Process Utilities

  • Heavy Engineering

  • Industrial Manufacturing

  • EPC Projects

  • Plant Maintenance

  • Process Industries

The product is relevant to EPC contractors, engineering companies, fabrication contractors, OEMs, consultants, maintenance teams and industrial procurement departments.

Standards & Specifications

The primary dimensional and technical reference for spectacle blinds is ASME B16.48 – Line Blanks. The standard covers line blanks used between ASME B16.5 flanges and includes requirements relating to pressure-temperature ratings, materials, dimensions, tolerances, marking and testing. The published 2020 edition covered NPS 1/2 through NPS 24 and Classes 150, 300, 600, 900, 1500 and 2500.

Material selection is governed by the applicable material specification and project requirements. Depending on the selected material, ASTM specifications such as ASTM A105 for carbon steel forgings or ASTM A182 for certain alloy and stainless steel forgings may be specified. The exact material standard and grade must be confirmed from the purchase specification.

Quality Standards & Testing of Spectacle Blind Flange

Quality control focuses on material identity, geometry, thickness, dimensional compatibility and surface condition. Depending on the project specification, inspection can include:

  • Raw material verification

  • Chemical composition analysis

  • Mechanical testing

  • Tensile testing

  • Hardness testing where applicable

  • Dimensional inspection

  • Thickness measurement

  • Bore and outside-diameter inspection

  • Facing inspection

  • Visual inspection

  • PMI testing where required

  • Marking verification

  • Third-party inspection where specified

  • Mill Test Certificate documentation

  • Heat and lot traceability

Nishra Overseas states that it provides original MTCs, PMI testing, third-party inspection acceptance and material traceability through heat and lot marking. The company also states that it is ISO 9001:2015 certified.

How to Select the Right Spectacle Blind Flange

Before ordering a spectacle blind, industrial buyers should confirm:

  • Size: Match the nominal pipe size and mating flange dimensions.

  • Pressure Class: Select the required class based on design pressure and temperature.

  • Material: Match the material with the process fluid and corrosion environment.

  • Grade: Confirm the specified ASTM or project material grade.

  • Facing: Check RF, RTJ or another required facing configuration.

  • Standard: Specify ASME B16.48 or the applicable project standard.

  • Thickness: Verify against the applicable line-blank dimensions.

  • Service: Consider pressure, temperature and process conditions.

  • Inspection: Specify MTC, PMI, NDE or third-party inspection where required.

  • Quantity: Provide project quantity and required delivery schedule.

Correct selection ensures that the spectacle blind is dimensionally compatible with the piping assembly and suitable for the intended service conditions.

Why Choose Nishra Overseas for Spectacle Blind Flange?

Nishra Overseas brings more than 25 years of industry experience to industrial piping product supply. The company is ISO 9001:2015 certified and states that it supports buyers with original Mill Test Certificates, PMI testing, third-party inspection acceptance and heat-and-lot material traceability.

Key procurement support includes:

  • 25+ years of industry experience

  • ISO 9001:2015 certification

  • Original Mill Test Certificates

  • PMI testing where required

  • Material traceability

  • Third-party inspection acceptance

  • Technical support

  • Industrial project supply

  • Export capability to 50+ countries

Spectacle Blind Flange Supply for Industrial Projects in Mumbai

Nishra Overseas supplies Spectacle Blind Flange in Mumbai for refinery maintenance, plant shutdowns, EPC projects, process piping installations, pipeline isolation requirements and industrial expansion projects.

Project procurement teams can provide the piping class, nominal size, pressure class, material grade, facing type, applicable standard, quantity and inspection requirements. This allows the required line blank configuration to be matched with the surrounding piping system.

Get a Quote for Spectacle Blind Flange in Mumbai

Looking for a Spectacle Blind Flange Manufacturer in Mumbai, Spectacle Blind Flange Supplier in Mumbai, or Spectacle Blind Flange Exporter in Mumbai? Contact Nishra Overseas for technical assistance and a project-based quotation.

For a quotation, provide:

  • Product type

  • Material and grade

  • Nominal size

  • Pressure class

  • Facing

  • Applicable standard

  • Quantity

  • Drawing or piping specification

  • Inspection requirements

  • Delivery location

Nishra Overseas LLP
302, 3rd Floor, A Wing, Rajgiri Apartment, 13th Khetwadi Back Road, Mumbai 400004, India
Phone: +91-7021931392
Email: sales@nishraoverseas.com