ASTM A350 LF2 Flanges Supplied to Singapore Across Multiple Pressure Classes

A Singapore customer recently received a mixed flange order from Haihao Group covering ASTM A350 LF2 flanges, blind flanges, spectacle blinds and a paddle spacer. The order moves from 150# to 1500# and 2500#, combines RF and RTJ facings, and uses different bore or thickness requirements across relatively small nominal sizes.

Most of the flange items are ASTM A350 LF2 Class 1, while the isolation components are ASTM A516 Grade 70 and the 6-inch 2500# RTJ weld neck flange is ASTM A694 F60. The dimensional standards are ASME B16.5 or ASME B16.48 as specified in the purchase order.

The Same LF2 Material Does Not Mean the Same Flange

The largest group in this Singapore shipment uses ASTM A350 LF2 Class 1, but the specifications vary considerably.

The order includes:

• 3″ XS WN RF, 150#
• 3/4″ SCH 160 WN RF, 1500#
• 4″ XXS WN RTJ, 1500#
• 2″ SCH 160 WN RF, 600#
• 1″ SCH 160 WN RF, 150#
• 2″ SCH 160 WN RF, 150#
• 1 1/2″ SCH 160 WN RF, 300#
• 1 1/2″ XXS WN RTJ, 1500#
• 3″ 1500# blind RTJ
• 3/4″ SCH 160 WN RF, 150#
• 3/4″ 150# blind RF
• 6″ × 3/4″ 150# blind RF drilled for a branch connection
• 6″ XXS WN RTJ, 1500#

This is why a purchase description such as “A350 LF2 flange” is only the starting point. The nominal size, pressure class, facing, flange type and bore or wall-thickness designation all need to remain attached to the material grade.

For example, a 2″ SCH 160 WN RF 600# flange and a 2″ SCH 160 WN RF 150# flange share the same nominal size, bore designation and material, but they are not interchangeable items in a purchase order.

The Order Also Includes B16.48 Isolation Components

Not every item in the shipment is a flange.

Haihao Group also supplied:

• 6″ 300# spectacle blind, FF, ASTM A516 Grade 70, ASME B16.48
• 18″ 150# paddle spacer, FF, ASTM A516 Grade 70, ASME B16.48

These components should not simply be grouped under the same product description as the B16.5 flanges. Their governing standard in the order is ASME B16.48, and the material is ASTM A516 Grade 70.

The distinction is useful when reviewing a piping material requisition because flange standards and line-blind standards serve different product categories. Keeping the standard and material visible in the item description helps prevent substitutions during purchasing and packing.

One 2500# RTJ Flange, Different Material

The order contains one further specification worth separating from the LF2 group:

6″ × 1″ THK WN RTJ, 2500#, ASTM A694 Grade F60, ASME B16.5.

This flange has a different material grade from the other WN RTJ items in the shipment. The pressure class is also the highest in the order.

That makes it a good example of why material and pressure class should never be inferred from one another. A 2500# designation does not mean the flange automatically belongs to the A350 LF2 group; the purchase order must identify the actual material specification.

ASTM A694 F60 is also commonly listed for high-pressure B16.5 flange applications, including 1500# and 2500# classes.

Singapore Flange Order at a Glance

Product Group	Representative Specifications	Material	Standard
WN RF Flanges	3/4″–3″, 150#–1500#, SCH 160/XS	ASTM A350 LF2 CL1	ASME/ANSI B16.5
WN RTJ Flanges	1 1/2″–6″, 1500#, XXS	ASTM A350 LF2 CL1	ANSI B16.5
Blind Flanges	3/4″ 150# RF; 3″ 1500# RTJ	ASTM A350 LF2 CL1	ASME/ANSI B16.5
Special Blind Flange	6″ × 3/4″, 150# RF, drilled	ASTM A350 LF2 CL1	ASME B16.5
Spectacle Blind	6″, 300#, FF	ASTM A516 Gr.70	ASME B16.48
Paddle Spacer	18″, 150#, FF	ASTM A516 Gr.70	ASME B16.48
WN RTJ Flange	6″, 1″ THK, 2500#	ASTM A694 F60	ASME B16.5

What to Send When Requesting a Flange Quote

For a similar ASTM A350 LF2 flanges requirement, the fastest way to obtain an accurate quotation is to provide the complete flange description rather than only the nominal size.

At minimum, include:

• Nominal pipe size
• WN, blind or other flange type
• RF, RTJ or FF facing
• Pressure class
• SCH, XS, XXS or specified thickness
• Material grade and class
• Applicable dimensional standard
• Special drilling or machining requirements, if any

This is particularly important when one project combines 150#, 300#, 600#, 1500# and 2500# components. A detailed material list allows the manufacturer to distinguish similar-looking items before production starts.

Haihao Group supplies ASTM A350 LF2 flanges in multiple sizes, pressure classes and facing configurations, together with ASME B16.48 isolation components and other forged pipeline products. For your next RFQ, send the flange schedule, drawings or item list with size, class, facing, material and standard requirements, and Haihao Group can review the specifications for quotation.