Black Iron (BI) Pipes

BI pipes are primarily used for fire sprinkler systems and natural gas lines because they resist high heat. Locally, they are also popular for structural framing, handrails, and industrial scaffolding where the pipe will be painted or kept away from constant moisture.

Strength & Durability:
High Carbon Steel Construction: Black iron pipes (BI pipes) are made from hot-rolled or cold-rolled carbon steel. This construction material offers exceptional strength and can withstand high pressure and heavy loads. This makes them ideal for critical applications like plumbing and gas lines of buildings.
Resistance to Bending and Cracking: The Black Iron Pipes’ robust construction makes them less prone to bending, cracking, or breaking than some plastic alternatives. This ensures reliable performance and minimizes the risk of leaks or structural failure in buildings.
Corrosion Resistance:
Iron Oxide Coating: Black iron pipes develop a natural rust layer during manufacturing. This offers some corrosion protection especially in places without moisture. For wetter environments, galvanized pipes provide overall better protection.
Affordability:
Cost-Effective Material: Compared to other options like copper or stainless steel, black iron pipes are a more affordable choice. This makes them a good value proposition for many plumbing and gas line applications, especially in larger construction projects.
Versatility:
Wide Range of Applications: Black iron pipes are not limited to just plumbing and gas lines as they can be used in various applications, including fire sprinkler systems, compressed air systems, and even for structural purposes due to their sturdiness.
Easy to Thread and Connect: Black iron pipes are relatively easy to thread and connect using standard pipe fittings. This allows for a secure and reliable connection, thereby simplifying pipe installation.
Fire Resistance:
High Melting Point: Black iron pipes excel in fire resistance. Their high steel melting point makes them ideal for fire sprinkler systems, helping contain fires and safeguard property.
While black iron pipes boast strength, durability, and affordability, they are susceptible to rust in damp environments and can be heavier than plastic alternatives. However, their numerous advantages often outweigh these limitations, making them a popular choice in construction.

Neither is “better” overall; it depends on the environment. GI (Galvanized Iron) is superior for outdoor or water-exposed areas due to its protective zinc coating. BI is better for gas lines and indoor structural use where cost-savings are prioritized and rust is less of a risk.

In local construction, Schedule 40 and Schedule 80 are the most common. The “schedule” refers to the wall thickness. You will also occasionally see Schedule 20 for light structural work, but 40 is the standard for most plumbing and industrial applications in the Philippines.

Schedule 80 clearly provides a greater strength due to its thicker wall thickness providing greater resistance against higher internal pressures as well as greater external stresses applied to them. While it will cost you more than a schedule 40 pipe, this pipe is used mainly on heavy duty industrial applications and also highly pressured fluid transfers.

For outdoor gates, fences, or trusses that are subject to the high humidity of the Philippines, we strongly recommend using GI tubular material as it is more resistant to rusting than BI material. However, if the application consists solely of indoor furniture or framing, and you plan on priming and painting the wood, you will get a much smoother finish with BI, and therefore will be more cost effective.

Yes. BI pipes do rust because they do not have any zinc coating to protect from rusting. The rusting process occurs because of the exposure to moisture or oxygen in the environment. To avoid kalawang (rust) in the Philippines if you use BI pipe in areas where there is high humidity and exposure to the elements, you should have them properly primed and painted before use.