ANSI Class 150 Flange Dimensions PDF Threaded Small Bore Pipe Guide

ANSI Class 150 Flange Dimensions Complete Reference

ANSI Class 150 flanges are the most widely used flange type in industrial piping. This guide provides complete dimensional data, PDF references, and selection information for engineers and procurement professionals.

Class 150 Flange Overview

ANSI/ASME B16.5 Class 150 flanges are designed for low to medium pressure applications:

Pressure Rating

• Maximum working pressure: 285 psi at ambient temperature
• Hydrostatic test pressure: 450 psi
• Temperature range: -20°F to 800°F (-29°C to 427°C)
• Pressure decreases at elevated temperatures

Common Materials

• Carbon Steel: ASTM A105, A350 LF2
• Stainless Steel: A182 F304/304L, F316/316L
• Alloy Steel: A182 F11, F22, F91
• Duplex: A182 F51, F53

Complete Dimension Tables

NPS 1/2 to NPS 24 Class 150 Dimensions

NPS	DN	OD	BC	Bulloni	Hole	Thick
1/2	15	3.50	2.38	4	0.62	0.44
3/4	20	3.88	2.75	4	0.62	0.50
1	25	4.25	3.12	4	0.62	0.56
1.1/4	32	4.62	3.50	4	0.62	0.56
1.1/2	40	5.00	3.88	4	0.62	0.62
2	50	6.00	4.75	4	0.75	0.62
2.1/2	65	7.00	5.50	4	0.75	0.69
3	80	7.50	6.00	4	0.75	0.75
4	100	9.00	7.50	8	0.75	0.81
5	125	10.00	8.50	8	0.75	0.88
6	150	11.00	9.50	8	0.88	0.94
8	200	13.50	11.75	8	0.88	1.06
10	250	16.00	14.25	12	0.88	1.12
12	300	19.00	17.00	12	1.00	1.12
14	350	21.00	18.75	12	1.12	1.19
16	400	23.50	21.25	16	1.12	1.31
18	450	25.00	22.75	16	1.25	1.44
20	500	27.50	25.00	20	1.25	1.56
24	600	32.00	29.50	20	1.38	1.69

Note: All dimensions in inches. OD=Outside Diameter, BC=Bolt Circle, Hole=Bolt Hole Diameter, Thick=Flange Thickness

Threaded Flange for Small Bore Pipe

Threaded flanges are ideal for small diameter piping where welding is impractical:

Size Range

• Available: NPS 1/2 to NPS 4 (DN15 to DN100)
• Pressure classes: 150, 300, 600, 900, 1500, 2500
• Thread types: NPT, BSP, PT

Applications

• Instrument connections
• Sample points
• Drain and vent lines
• Installazioni temporanee
• Hazardous areas (no hot work)
• Compressed air systems
• Water distribution

Installation Tips

1. Clean threads on both flange and pipe
2. Apply PTFE tape or thread compound
3. Hand-tighten first, then wrench
4. Leave 1-2 threads exposed
5. Do not overtighten

Flange Repair and Machining Service

Professional repair services extend flange life and reduce replacement costs:

Repair Capabilities

• Face Resurfacing: Repair damaged sealing surfaces
• Bore Machining: Restore proper pipe fit
• Bolt Hole Repair: Fix stripped or damaged holes
• Weld Overlay: Build up worn surfaces
• Re-drilling: Modify bolt patterns

When to Repair vs Replace

• Minor surface damage: Repair
• Severe corrosion: Replace
• Cracked flange: Replace
• Dimensional out of tolerance: Repair or replace

Carbon Steel Flange Suppliers

Finding reliable suppliers ensures quality and competitive pricing:

Supplier Selection Criteria

1. Manufacturing capabilities and certifications
2. Material traceability (MTR available)
3. Quality control procedures
4. Production capacity and lead times
5. Export experience and references
6. After-sales support

Price Indicators

• Raw material costs (steel prices)
• Manufacturing complexity
• Surface treatment requirements
• Quantity and size
• Certification requirements

Stainless Steel Flange Manufacturers by Country

Major Manufacturing Regions

• China: Largest producer, competitive pricing
• India: Growing capacity, good quality
• Italy: Premium quality, higher cost
• USA: Domestic supply, quick delivery
• Japan: High precision, excellent quality

Corrosion Resistant Flange for Marine Use

Marine environments require superior corrosion resistance:

Recommended Materials

• 316/316L: General marine applications
• 2205 Duplex: Offshore platforms
• 2507 Super Duplex: Severe conditions
• 904L: Chemical tankers
• Aluminum Bronze: Propeller shafts

Protective Measures

• Cathodic protection systems
• Protective coatings
• Regular inspection and maintenance
• Sacrificial anodes

Download Resources

• ASME B16.5 dimension charts (PDF)
• Material selection guides
• Installation procedures
• Inspection checklists

Songhai Flange supplies ANSI Class 150 flanges in all sizes with complete dimensional certification. Threaded flanges available for small bore applications. Contact us for repair services and marine-grade corrosion resistant options.