Unknown facts about steel and ductile pipes

All pipe materials are not equal. Many people think that there is not much difference between different pipe materials. The reason behind it would be that people do not take much interest or do not go in deep facts. There are some technical facts which differentiate steel pipes from ductile iron pipes. Here are some unknown and interesting facts about steel pipes and ductile iron pipes.

• Cost effectiveness

One perspective to look at both pipe materials is, cost. Cost plays a very significant role in choosing a pipe material. Steel pipelines often require cathodic protection system which involves higher design and installation cost. They require a life time monitoring and maintenance and hence increased cost. Cement-mortar lined ductile iron pipe has an inside diameter larger than nominal pipe size. However, steel pipe inside diameter is equal to nominal pipe size. Therefore, for a given flow, velocity will be greater in steel than in ductile iron pipe. Higher velocities means higher head losses and when this difference is taken into account, ductile iron pipe delivers significant savings through lower pipelines head losses.

• Back filling is easier in ductile iron pipe

Pipe material’s modulus of elasticity and the moment of inertia has a function called pipe stiffness. Ductile Iron pipe is a stiffer product than steel pipe because ductile Iron pipe design results in a thicker wall for a given set of parameters. Ductile Iron pipe is a stiffer product, hence, it relies less heavily on the sidefill soils to help support the external load. However, steel pipe requires more design with regard to laying conditions. Where the maximum standard modulus of soil reaction, E’, for Ductile Iron pipe is 700 psi per ANSI/AWWA C150/ A21.50, this is more nearly a minimum condition for steel pipe.

• Ductile iron pipelines adapt to field conditions in installation

Ductile Iron pipe has deflectable push-on and mechanical joints. This means that the ample deflection capabilities of the joints may be used to help reroute the pipe around existing underground obstructions, such as existing utilities. It provides more flexibility to the contractor than steel pipe can offer. It also eliminates the common need for special lengths of pipe to be manufactured and shipped.

• Difference in length

Ductile Iron pipe is furnished in 18 to 20 foot nominal laying length. On the other hand, steel pipe can be furnished in 20 foot length, however, is more commonly offered in 36 to 50 foot length. This exacerbates handling concerns.

There are plenty of advantages of Ductile Iron pipe. The conservative design approach gives the engineer an effective design that is easily accomplished while offering an impressive factor of safety.

Why use galvanized steel pipe?

Galvanized steel is simply steel coated with zinc. After going through a process called galvanizing, in which steel is coated with zinc and a normal steel becomes a galvanized steel. This process is performed to avoid steel from rust and corrosion.

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Galvanized steel has thousands of industrial applications, especially marine products. They are commonly used in marine applications because in that case the pipe fittings are subject to tough and wet conditions. It is not a new concept, in fact, it is being used from early times. Till 1850, over ten million tons of zinc was used to protect steel. There is a misconception about the galvanized steel.

Many people think that galvanized is a better product, but it is expensive and increases the overall cost. In fact, galvanized steel becomes less expensive when combined with its long life span. Galvanized steel studs cost almost half the price as compared to wooden studs that are most commonly used in buildings. Galvanized pipes are not used for  underground lines. It is relatively better to use for hot water lines, however, it also works good for cold water lines. Avoid using galvanized pipe fittings for gas supply lines as natural gas can cause the zinc to come off and cause blockages in the system.

Galvanized pipe fittings generally comes in size ranging from diameter of 1/8" to 20". These pipes are great value for money. No doubt galvanized steel pipes have various advantages, however, it has disadvantages also. One disadvantage is that the zinc coating can hide problems and defects beneath the coating which would otherwise be visible. And there are few more.

The important thing to remember is that whatever you choose, choose smartly. There is nothing on this planet that has only advantages, But there are things that have more advantages than disadvantages which makes them relatively better choice.

Why build green: Benefits of green building

Investors are realizing the need for going green to help reduce pollution from the environment. It not only helps make healthy buildings, but also develops a reputation and image of investors in the market. Image and reputation is a big thing in a market. This is only one advantage of building green, other benefits are:

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1. Environmental Benefits

As the name suggests, building green has various advantages. Like clear environment, improved air and water quality, reduced waste, conserve and restore natural resources.

2. Lower building cost

Some people think that green building costs higher, but the fact is that green building costs lower. It is true that the initial cost is high, but in the long run the cost gets lower and lower.

3. Improves productivity and attracts brilliant employees

According to a research, organizations in green buildings have an edge in attracting and retaining good employees. It is obvious that employees who are healthy and comfortable are more productive. It is proved by a number of studies. 31 green buildings from the City of Seattle were selected for the test and found that absenteeism was reduced by 40 percent. Another study which was sponsored in part by commercial real estate giant, Cushman & Wakefield, reported that 30 percent fewer sick days among one company's employees, and discovered a 10 percent increase in net revenue per employee in another company.

4. Sick building syndrome

This is a problem that is commonly present in non-green buildings. It has cost businesses millions of dollars each month. However, in green buildings with proper lighting, ventilation and use of non-toxic materials, you can totally avoid such problems.

5. Higher market value and reduced tax

Green buildings have a high image and reputation in the market as well as in the society. With high image, high prices are certain and also high resell value. Governments have enacted federal tax incentives to encourage the design and construction of energy-efficient green buildings, both residential and commercial.

6. Improved Quality of life

With green lighting, quality air to breath, reduced use of toxic materials and comfortable environment surely improves quality of life. It also improves quality of work life (Q.W.L).

How steel pipes have a lower safety factor?

Safety is the first and the foremost factor you consider before doing anything. May it be investment in the stock exchange or going on for a ride or doing the all new construction. If you recall the Maslow’s hierarchy of needs, you will see that after the physiological needs, the second human need is safety and security.

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This factor of safety increases to the highest when it comes to construction and buildings. Because it is not only about the strength of the building, but also the safety of human lives. The most important thing is human lives and you cannot compromise on that in any exchange. In construction and building, if you talk about steel pipes vs. ductile iron pipes, the steel pipes have a lower safety factor.

When steel pipes and Ductile Iron pipes are bid against each other owners and engineers are often hectic with the information relating to different aspects of these two materials. Many people are unknown to the actual facts, but the facts are facts. And sometimes facts are hard to come by. Whether the concern is engineering, installation, safety or operation, an objective comparison of these two materials shows they are not equal. Conservative design and ease of installation feature of ductile Iron pipes make it decidedly better than steel pipe or tubes.

Ductile Iron pipe has a standardized design procedure (ANSI/AWWA C150/A21.50), and the approach in that standard is the most conservative in the piping industry. When it comes to steel pipe, working pressure design is based on 50% of the steel yield strength, a factor of safety of 2.0. However, it is important to note that surges are allowed to increase the stress in the pipe wall to a maximum of 75% of yield. In the process, allowing the wall stress to increase to 75% of yield. This is as same as reducing the factor of safety in design to 1.33.

The factor of safety in design will vary from a maximum of 2.0 i.e. zero surges, to as little as 1.33. In either case, steel pipe or tube design allows surges to compromise the factor of safety.

Why use seamless steel pipes and tubes?

Seamless steel pipes are stronger and better than welded pipes. That is why they are preferred by industries looking for stronger alternatives. Seamless steel pipes and tubes are used in variety of areas. They are used in aircraft, missiles, anti friction bearing, machine parts and high pressure cylinders.

Seamless steel pipes have various benefits. They are stronger, more reliable, durable and work best for heavy duty activities. The outside diameter of most of these seamless tubes is 1/8 to 26 inch. One of the major benefit of seamless steel tube is the increased pressure ratings.

Welded seam is the weakest point in a welded pipe. Most leaks and pipe failures happen at the welded seam. A seamless pipe does not have a seam and that is why the tensile strength is uniform around the entire pipe. Using seamless pipe is more expensive but allows for smaller wall thickness and pipe weight, which can affect cost as well as design. Even though, seamless pipes are most expensive pipes in steel pipes, yet it is the most reliable and trusted with fewer failure points. Another benefit is that pressure calculations are easier.

Not to forget its strength under loading. When it begins transporting material, the weight of the material must also be taken into account.

What is the importance of steel pipes and tubes in heavy industries?

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Steel pipes are famous for its strength. Its strength makes it more demanding and useful in variety of areas. Talking about its applications, you must have heard about "jack and bore" construction, in which the pipe is pushed with a hydraulic ram, while an auger spins inside the pipe and carries the displaced soil back to the jacking pit, where it can be easily removed.

It is also used to transport water. And not to forget its ability to be recycled. Steel is protected in two ways to prevent corrosion and increase strength, by galvanization or by making it into an alloy. There are various types of steel. Galvanized steel is only coated, whereas alloys are combination of steel and carbon. Super deluxe is a super steel alloy, made by modifying metal alloys. Although these are superior in use, but the cost is high.

Another type is stainless steel. They are made from steel-chromium alloy. It is the cheapest of all. Carbon steel is another type which is extremely malleable and can be used to form small precision components. Organizations try to be cost effective and to do this, the cost against safety, effectiveness and longevity has to be balanced.

Why use steel pipe and tube fittings?

Steel pipe or tube is a building material made from an alloy of iron and carbon. Steel pipes are also called steel tubes in some part of the world. There are variety of steel products. It is used in variety of manufacturing and industrial applications. The reason for its variety of uses is that, it can be easily grooved, cut and threaded in size, on-site.

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However, steel pipes are widely used for construction purposes, they are also very commonly used in transporting liquid and gases from one location to another. This material is also used as a structural component for scaffolding and framing systems. The most famous project for transporting petroleum products is the Trans-Alaska pipeline. These transmission pipes have a diameter of 48" and larger. And it is 800 miles long.

It is one example from many. Steel pipe is hollow and has a relatively low strength to weight ratio, hence, steel pipe engineers can design it for many uses. It can be used on a large scale as well as small scale. A real life example for large scale would be the support pole of massive highway billboards and small scale example would be a bicycle frame tube. Steel pipe's strength and rigidity allows it to be pushed under roadways and railroads without traffic disruption.

Not to forget its ability to be recycled. Steel pipes are recyclable and have high reclamation rate. Recycling is not only important for the economic purpose, but environmental factors also force us to use things which are recyclable easily.