GI Pipe Schedule 20 vs Schedule 40: A Guide for Choosing the Right Steel Pipe

The strength, durability, and safety of your project start with using the correct GI pipe schedule.

Key Takeaways:

• GI pipe schedules define wall thickness, not diameter, directly affecting strength, pressure capacity, and durability.
• Schedule 20 is suited to light-duty, non-pressurized applications, while Schedule 40 is ideal for structural and high-load applications.
• Selecting the right schedule improves safety, efficiency, and long-term value while avoiding unnecessary costs.

Choosing the right galvanized steel (GI) pipe schedule is one of the most important decisions in construction and industrial applications. From small hardware store projects to large-scale real estate developments, galvanized steel pipes play a critical role in ensuring strength and safety.

Let’s explore everything you need to know about GI pipe schedules and understand the difference between GI pipe Schedules 40 and 20, so you can choose the right pipe for your project.

What is a Galvanized Steel (GI) Pipe Schedule?

A GI pipe schedule refers to the standardized wall thickness of a galvanized steel pipe. Contrary to what many assume, the schedule does not indicate the pipe’s diameter. Instead, it specifies the pipe wall thickness, which directly affects strength, pressure capacity, and weight.

Pipe schedules are globally recognized standards. Among the most commonly used in the country are Schedule 20 and Schedule 40.

Common Types of GI Pipe Schedules

Exploring the most widely used GI pipe schedules helps ensure that the pipe you select aligns with your project’s structural, functional, and budget requirements.

GI Pipe Schedule 20

GI pipe Schedule 20 is considered a light-to-medium-duty pipe. It has thinner walls than higher-schedule models, making it lighter and easier to handle.

One of the most frequently asked specifications is the thickness of schedule 20 GI pipe in mm. While exact thickness varies by nominal pipe size, Schedule 20 pipes generally have thinner walls, making them suitable for non-pressurized and low-load applications.

Because of its lighter weight, Schedule 20 is often chosen for projects where ease of installation and cost efficiency are priorities.

GI Pipe Schedule 40

GI pipe Schedule 40 is the industry standard for heavier-duty applications. It has thicker walls and higher structural strength.

The GI pipe Schedule 40 thickness (mm) is greater than that of Schedule 20, allowing it to withstand higher pressure, impact, and load-bearing requirements. This added thickness also increases durability in outdoor and industrial environments.

Schedule 40 is widely used in construction, mechanical systems, and applications where safety and longevity are critical.

GI Pipe Schedule 20 vs. Schedule 40:Key Differences

Understanding GI Pipe Schedule 20 vs. Schedule 40 helps prevent costly mistakes. Below is a comparison to guide your decision-making.

Feature	GI Pipe Schedule 20	GI Pipe Schedule 40
Wall Thickness	Thinner	Thicker
Weight	Lighter	Heavier
Strength	Moderate	High
Pressure Capacity	Low to medium	Medium to high
Typical Uses	Furniture, light framing, and fencing	Plumbing, structural support, and industrial use
Cost	More affordable	Higher initial cost, longer lifespan

Another critical factor is weight. Many buyers ask about the weight in kg of Schedule 40 GI pipes, as heavier pipes affect transportation, handling, and structural load capacity. Schedule 40 pipes weigh more per meter than Schedule 20 pipes due to their thicker walls.

Typical Uses of GI Pipe by Schedule

Different industries rely on specific GI pipe schedules depending on performance requirements, safety standards, and project lifespan.

Construction and Real Estate

In residential and commercial construction, GI pipes are used for structural framing, railings, fencing, and plumbing systems.

Schedule 20 pipes are commonly used for non-load-bearing components such as gate frames, ceiling supports, and temporary structures. Schedule 40 pipes are preferred for water lines, handrails, and structural reinforcements that require higher strength.

Real estate developers often specify Schedule 40 for long-term infrastructure projects because it offers greater durability and better compliance with building standards.

Hardware Stores and Local Suppliers

For hardware store owners outside mall-based retail, stocking both Schedule 20 and Schedule 40 GI pipes allows you to serve a broader range of customers. DIY builders, contractors, and small business owners often seek affordable Schedule 20 options, while professionals typically specify Schedule 40 for critical installations.

Reliable sourcing from a trusted steel supplier ensures consistent quality and repeat business.

Furniture Manufacturing

The furniture industry relies heavily on GI pipes for modern and industrial-style designs. Tables, shelving units, bed frames, and display racks often use Schedule 20 pipe because it is easier to cut, bend, and weld.

However, for furniture that carries heavier loads, such as commercial shelving or hospital furniture, Schedule 40 offers better structural integrity.

Medical and Healthcare Facilities

In medical environments, GI pipes are used for handrails, equipment frames, partitions, and utility supports. Durability, cleanliness, and corrosion resistance are essential.

Schedule 40 GI pipes are commonly selected for hospital infrastructure due to their strength and longer service life, especially in areas subject to frequent cleaning and moisture exposure.

Benefits of Choosing the Right GI Pipe Schedule

Identifying the correct GI pipe schedule offers several advantages beyond cost savings.

• Ensures structural safety by using pipes with the appropriate wall thickness for load and pressure requirements
• Improves project efficiency by avoiding overengineering that adds unnecessary weight and expense
• Extends service life by reducing premature wear, corrosion exposure, and maintenance needs

Whether you choose GI pipe Schedule 20 or GI pipe Schedule 40, the key is to match the pipe’s capacity to its intended use.

Why Source Your GI Pipes from Global Nexus

Global Nexus is a trusted name in the Philippine steel industry, supplying high-quality materials to construction firms, hardware retailers, and industrial clients nationwide.

As a reliable steel supplier, Global Nexus offers a wide range of GI pipe options that meet strict quality standards. Their galvanized steel pipes are designed for strength, corrosion resistance, and consistent performance across applications.

Unlike mass-market suppliers, Global Nexus focuses on long-term partnerships. Clients benefit from expert guidance, dependable supply, and products that align with project requirements.

Get the Right GI Pipe Schedule for Your Next Project

Selecting the right GI pipe schedules is essential for building safer, stronger, and more cost-effective projects. By knowing the differences in thickness, weight, and application between Schedule 20 and Schedule 40, you can make informed decisions that support both performance and budget goals.

Work with Global Nexus, a trusted steel supplier in the Philippines, to access high-quality galvanized steel pipes and expert support for your projects. Contact us today to inquire about GI pipes and other steel solutions built for reliability and long-term value.

Frequently Asked Questions about GI Pipe Schedule

1. What is the difference between GI pipe Schedule 20 and Schedule 40?

The main difference lies in wall thickness. GI pipe Schedule 40 has thicker walls than Schedule 20, making it stronger and capable of handling higher pressure and load requirements. Schedule 20 is lighter and more cost-effective, best suited for non-structural and low-pressure applications.

2. Which GI pipe schedule is better for construction projects?

For structural, plumbing, and load-bearing applications, GI pipe Schedule 40 is generally preferred due to its higher strength and durability. Schedule 20 may be used for non-load-bearing components such as frames, fences, and temporary structures where lower weight and cost are priorities.

3. Does a higher GI pipe schedule mean a larger diameter?

No. The pipe schedule does not determine the diameter of the GI pipe. Instead, it indicates wall thickness. Pipes with the same nominal diameter can have different schedules, resulting in varying strengths, weights, and pressure capacities.

4. Can GI pipes be welded, cut, or bent on-site?

GI pipes can be cut, welded, and bent using standard steel fabrication tools. When welding, the zinc coating around the joint is typically removed and reapplied afterward to maintain corrosion protection and ensure a clean weld.

5. How do I choose the correct GI pipe size for my application?

Determining the correct pipe size depends on factors such as load requirements, intended use, space constraints, and applicable building codes. Consulting with a steel supplier or project engineer helps ensure the pipe size meets both safety and performance standards.