Big Ton Spring Supports for an Oil Refinery in Australia

July 2, 2018

PT&P Custom Designed Big Ton Spring Supports for an Oil Refinery in Australia

Type: Big Ton Spring Supports
Material: Carbon Steel w/ HDG Finish
Design: 13,457 lb. Load | 0.35" Vertical
Testing: Load and Travel Tests

These big ton springs are used in supporting large heavy units such as compressors, vessels and pumps in power and petrochemical plants. The housing and frame are fabricated from carbon steel and hot-dipped galvanized, and the spring coils are dipped in a neoprene coating. The units are 48” x 40” x 20”. The big ton spring support is designed to allow limited movement of 0.35″ upwards and an operating load of 13,457 lb. This design saved the customer from having to entirely redesign the piping system, which saved them thousands of dollars. Load and travel tests were performed prior to shipping to an oil refinery in Australia.

Big Ton Spring Supports Custom Designed for a Chemical Plant in Singapore

December 26, 2017

Big Ton Spring Supports Custom Designed for a Chemical Plant in Singapore

Type: Big Ton Spring Supports
Material: Carbon Steel/SAE 5160H
Design: 44mm up & Operating Load 130,642 N
Testing: Standard Load & Travel Tests

PT&P custom designed big ton spring supports for a chemical plant in Singapore. These types of supports are used in supporting large heavy units such as compressors, vessels and pumps in power and petrochemical plants. The materials that were used are a carbon steel housing and frame with spring coil- SAE 5160H. The big ton spring support is designed to allow limited movement of 44 mm up with operating load of 130,642 N. By doing this, it’s saving the customer from having to entirely redesign the piping system and saving thousands of dollars. This custom big ton design was shipped in 6 weeks.

Engineered Spring Supports (Practical, Hands-on Approach) Webinar

November 27, 2017

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video to view the webinar in full-screen mode.

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View the Slides for Above Webinar Here

Corrosion Protection

October 9, 2017

Corrosion protection

This technical bulletin will consider four methods of protecting carbon steel pipe supports components from corrosion; painting, zinc coatings, hot dip galvanizing, and combinations of these. Painting has an advantage when appearance and choice of color are important. Modern painting systems may be appropriate protection in certain environments. Paint provides “barrier” protection to a metal surface. The ability of zinc to provide cathdoic protection for carbon steel in addition to barrier protection is a fundamental advantage. In most cases the reduction in life-cycle costs justifies the small additional cost of galvanizing. Indeed painting and galvanizing together can provide a synergistic benefit which may be justified in some cases.

The use of zinc and galvanizing has a long history. The early patents for hot dip galvanizing were issued in France and England in 1836 and 1837. This technology was quickly adopted and was widely used in the late-1800s. In the United States we have bridges more than 100 years old which have galvanized structures. In addition, we have transmission towers and substation structures that are over 70 years old. A pipe rack at a petrochemical plant near Houston was studied after 28 years of service. Measurements of the zinc thickness remaining provided a forecast of another 60 years of service. Pulp and paper mills use galvanized materials in most of their critical environments. It is important to understand the fundamentals which make this “old” technology so cost effective in such a wide variety of applications.

Electrochemistry of Zinc & Carbon Steel

Corrosion is an electrochemical process which occurs when four elements are present; an anode which gives up electrons, a cathode which receives electrons, an electrolyte (which is usually an aqueous solution of acids, bases, or salts) and a metallic current path. The rate at which corrosion occurs depends on the electric potential between the anodic and cathodic areas, the pH of the electrolyte, the temperature, and the water and oxygen available for chemical reactions.

Effect of corrosion on carbon steel
Figure 1 indicates how corrosion damages carbon steel. Note that the pitted area to the right is anodic and gives up electrons while the cathodic area to the left (where water and oxygen from the air are present) is where rust appears. The pitted area where the carbon steel is weakened is not where the rust appears.
Zinc corrosionEffect of corrosion on zinc and carbon steel
Zinc has a greater tendency to give up electrons than carbon steel, so when both are present, zinc becomes the anode and protects the carbon steel. Figure 2 indicates corrosion with the zinc giving up the electrons and becoming pitted while the carbon steel remains undamaged. From this we see that a zinc coating will protect carbon steel by “sacrificing” itself until the zinc is depleted. The rate of zinc depletion is relatively slow when the pH of the electrolyte is between 4 and 13.

Hot dip galvanizing has two advantages over a zinc coating. During galvanizing, the molten zinc reacts with the carbon steel to form layers of zinc/iron alloys. Figure 3 shows a galvanized surface with 5 layers, the top layer is 100% zinc and the bottom layer is carbon steel. The alloy layers between have increased hardness to provide mechanical (barrier) protection and because of their zinc content they are also anodic relative to carbon steel. The hardness of these alloy layers provides much more protection from scratches than paint can provide. This is important for most pipe supports applications.

Picture of the galvanized surface on carbon steel
  • Eta layer 100: Zn 70 DPN hardness
  • Zeta layer 94% Zn 6% Fe 179 DPN hardness
  • Delta layer 90% Zn 10% Fe 224 DPN hardness
  • Gamma layer 75 Zn 25% Fe
  • Carbon Steel 159 DPN hardness

Any coating which provides a barrier to the moisture and oxygen in the air will help protect carbon steel from corrosion. A properly painted surface will provide a barrier, but it is subject to scratching from contact with hard objects. Figure 4 illustrates how rust can grow and damage a painted surface when corrosion begins because the paint barrier is broken by a scratch.

Effect of Rust on a steel surface
Figure 4

Zinc coating for steel

Figure 5 illustrates the cathodic protection provided when a galvanized surface is scratched.

Duplex Systems usually require painting over galvanizing. Some of our customers have specified a duplex system. This is more expensive but it can be justified for certain corrosive environments or for appearance. The American Galvanizing Association suggests the following “rule of thumb” to estimate the service life of a duplex system.

(Duplex System Service Life) = 1.5* (Service Life: HDG Only) + (Service Life: Paint Only)
*The synergistic multiplier of 1.5 is based on the barrier protection the paint provides for the galvanized surface.

At Piping Technology and Products Inc., many customers have returned painted variable and constant spring supports which could no longer function due to corrosion. Costs must be considered during the specification of coatings for pipe supports. The owner and operator of a facility should consider life-cycle costs. Pipe supports are usually a relatively small percentage of the total cost of installing and operating a power plant, petrochemical plant, paper mill or other major facility. The small additional cost of hot dip galvanizing the carbon steel components of pipe supports is most always a wise investment.

For more information you may want to contact the following organization:

American Galvanizing Association-AGA
12200 E. Illif #204 Aurora, CO 80014
ph 800-468-7732

National Association of Corrosion Engineers-NACE
1440 S. Creek Dr. Houston, Tx 77084
ph 713-492-0535

Comparative Corrosion Resistance Guide

October 2, 2017
Medium Concentration Temp. °F 304 Stainless 316 Stainless 410 Stainless 416 Stainless 430 Stainless Nickel Alloy 400 Nickel Alloy C-276 PVC High Density Polyethylene Polypropylene FRP (Extren® 500/525)
Acetic Acid 20% 70° Good Good Good Poor Good Fair Good Good Good Good Good
Acetic Acid 50% 70° Good Good Poor Poor Fair Good Good Poor Good Good
Acetic Acid 80% 70° Good Good Poor Good Fair Good Fair Fair Good
Acetic Acid 100% 70° Good Good Good Poor Good Fair Good Fair Good Fair
Acetic Acid 50% Boiling Fair Good Poor Poor Fair Good Fair Good Good Not Recommended
Acetic Acid 80% Boiling Poor Good Poor Poor Fair Good Poor Good Fair Not Recommended
Acetic Acid 100% Boiling Fair Good Poor Poor Fair Good Poor Fair Fair Not Recommended
Acetic Anhydride 90% 70° Good Good Poor Good Fair Good Poor Good Good Not Recommended
Acetic Anhydride 90% Boiling Good Good Fair Poor Fair Fair Good Poor Good Good Not Recommended
Acetic Vapors 30% Hot Fair Good Poor Fair Fair Poor Poor Not Recommended
Acetic Vapors 100% Hot Fair Poor Fair Fair Poor Poor Not Recommended
Acetone 70° Good Good Good Good Good Good Not Recommended Not Recommended Good Not Recommended
Acetone Boiling Good Good Good Good Good Good Poor Fair Fair Not Recommended
Acetylene 70° Good Good Good Good Fair Good Good
Alcohol 3 ½- 4 ½ % 160° Good Good Not Recommended
Alcohol, Ethyl 70° Good Good Good Good Fair Good Good Fair Good Not Recommended
Alcohol, Ethyl Boiling Good Good Good Good Fair Good Good Good Good Not Recommended
Alcohol, Methyl 70° Good Good Good Good Fair Good Good Good Good Not Recommended
Alcohol, Methyl 150° Fair Good Fair Fair Fair Good Good Good Good Not Recommended
Aluminum Molten Poor Poor Poor Poor Poor Poor Poor Poor Poor Poor
Aluminum Acetate Saturated 70° Good Good Fair Good Good
Aluminum Acetate Saturated Boiling Good Good Fair Fair Good
Aluminum Chloride 25% 70° Poor Fair Poor Poor Fair Good Good Good Good Good
Aluminum Chloride Saturated 70° Poor Poor Fair Good Good Good Good Good
Aluminum Fluoride 70° Fair Poor Fair Good Good Good
Aluminum Hydroxide Saturated 70° Good Good Good Poor Fair Good Good Good
Aluminum Potassium Sulphate 2% and 10% 70° Good Good Good Poor Fair Good Poor Good Good
Aluminum Potassium Sulphate 2% and 10% Boiling Good Good Fair Poor Fair Good Good Good Good
Aluminum Potassium Sulphate Saturated Boiling Good Good Fair Poor Fair Good Good Fair Good
Aluminum Sulphate 10% 70° Good Good Poor Poor Fair Good Good Good Good
Aluminum Sulphate Saturated 70° Good Good Poor Poor Fair Good Good Fair Good
Aluminum Sulphate 10% Boiling Good Good Poor Poor Poor Good Good Fair Good
Aluminum Sulphate Saturated Boiling Good Good Poor Poor Poor Good Good Fair Good
Ammonia (Dry & Moist) All Concentrations 70°/212° Good Good Poor Good Poor Good Good Good Good Not Recommended
Medium Concentration Temp. °F 304 Stainless 316 Stainless 410 Stainless 416 Stainless 430 Stainless Nickel Alloy 400 Nickel Alloy C-276 PVC High Density Polyethylene Polypropylene FRP (Extren® 500/525)
Ammonia (Dry & Moist) Anhydrous 70° Good Good Poor Good Poor Good Fair Good Not Recommended
Ammonia (Dry & Moist) Anhydrous Hot Poor Poor Poor Poor Poor Good Not Recommended Good Not Recommended
Ammonium Bicarbonate 70° Good Good Poor Good Poor Fair Poor Good Poor Good
Ammonium Bicarbonate Hot Good Good Poor Good Poor Poor Poor Good Poor Not Recommended
Ammonium Carbonate 1%and 5% 70° Good Good Good Good Good Poor Fair Good Good Good Not Recommended
Ammonium Carbonate Aerated 70° Good Good Good Good Good Poor Fair Good Good Good Not Recommended
Ammonium Chloride 1% 70° Good Good Poor Good Good Good Good Good Good
Ammonium Chloride 1%/28%/50% Boiling Good Good Poor Fair Good Good Good Good
Ammonium Hydroxide 70° Good Good Good Good Good Not Recommended Fair Good Good Good Not Recommended
Ammonium Nitrates All Concentrations 70° Good Good Poor Good Poor Fair Good Good Good Good
Ammonium Nitrates Saturated Boiling Good Good Good Poor Good Poor Poor Good Good Good
Ammonium Oxolate 5% 70° Good Good Good Poor Good Fair Fair Poor Good Poor
Ammonium Perchlorate 5% 70° Good Good Good Good Good Fair
Ammonium Persulphate 5% 70° Good Good Good Poor Good Not Recommended Fair Good Good Good Not Recommended
Ammonium Phosphate 5% 70° Good Good Fair Good Fair Good Good Good Good Not Recommended

;

Ammonium Phosphate Saturated 70° Good Good Fair Good Fair Good Good Good Good Not Recommended
Ammonium Sulphate 1% and 5% 70° Good Good Fair Good Fair Fair Good Good Good Good
Ammonium Sulphate 10% Boiling Good Good Fair Fair Fair Fair Good Good Good Good
Ammonium Sulphate Saturated Boiling Good Good Fair Fair Fair Fair Good Poor Good Good
Ammonium Sulphite 70° Good Good Not Recommended Good Good Good
Ammonium Sulphite Boiling Good Good Not Recommended Good
Amyl Acetate Concentrated 70° Good Good Good Good Good Good Not Recommended Not Recommended Not Recommended
Amyl Chloride 70° Good Good Fair Fair Fair Good Not Recommended Not Recommended Not Recommended
Aniline 3% 70° Good Good Good Good Fair Fair Not Recommended Not Recommended Good
Aniline Conc. Crude 70° Good Good Good Good Fair Fair Poor Good Fair
Aniline Hydrochloride 70° Poor Poor Poor Poor Not Recommended Not Recommended Not Recommended Not Recommended
Antimony Molten Poor Poor Poor Poor Good Good
Antimony Trichlordie 70° Poor Poor Poor Poor Fair Fair Good Good Good
Arsenic Acid 150° Good Good Not Recommended Fair Good Good Good
Barium Carbonate 70° Good Good Good Good Fair Fair Good Good Good Good
Barium Chloride 5% 70° Good Good Fair Fair Good Good Good Good Good
Barium Chloride Saturated 70° Good Good Good Good Fair Good Good Good Good Good
Barium Chloride Aqueous Sol. Hot Good Good Fair Good Good Good Good Not Recommended
Barium Nitrate Aqueous Sol. Hot Good Good Poor Fair Fair
Medium Concentration Temp. °F 304 Stainless 316 Stainless 410 Stainless 416 Stainless 430 Stainless Nickel Alloy 400 Nickel Alloy C-276 PVC High Density Polyethylene Polypropylene FRP (Extren® 500/525)
Barium Sulphate 70° Good Good Good Good Fair Good Good Good Fair
Barium Sulphide Saturated 70° Good Good Good Good Good Poor Good Good Good Good Not Recommended
Barley-Malt & Hops 70° Good Good Good Good Good Good
Beer 70° Good Good Poor Good Good Good Good Good Good
Benzene 70° Good Good Good Good Good Good Fair Not Recommended Not Recommended Poor Not Recommended
Benzoic Acid 70° Good Good Good Fair Good Good Good Fair Good
Benzol 70° Good Good Good Good Fair Poor Poor Good
Blood (Meat Juices) Cold Good Good Good Good Good
Borax 5% Hot Good Good Good Good Good Good Good Good Good Good
Boric Acid 5% Hot Good Good Good Good Fair Good Good Good Good
Boric Acid Saturated Boiling Good Good Good Good Good Fair Good Good Good Good
Bromine 70° Poor Poor Poor Poor Poor Good Not Recommended Not Recommended
Buttermilk 70° Good Good Good Good Good Good
Butyric Acid 5% 70° Good Good Good Good Fair Good Not Recommended Fair Good Good
Butyric Acid 5% 150° Good Good Good Poor Fair Not Recommended Good Not Recommended
Butyric Acid. Aqueous Sol SP.G .964 Boiling Good Good Good Poor Poor Poor Poor Good
Calcium Carbonate 70° Good Good Good Fair Fair Good Good Good Good
Calcium Chlorate Dilute Sol. 70° Good Good Fair Fair Good Good Good Good
Calcium Chlorate Dilute Sol. Hot Good Good Fair Fair Good Good Good Good
Calcium Chloride Dilute Sol. 70° Good Good Fair Fair Good Good Good Good Good
Calcium Chloride Cone. Sol. 70° Good Good Fair Fair Good Good Good Good Good
Calcium Hydroxide 10% Boiling Good Good Fair Good Good Good Good Not Recommended
Calcium Hydroxide 20% Boiling Good Good Fair Good Good Good Good Not Recommended
Calcium Hydroxide 50% Boiling Fair Good Fair Good Good Good Good Not Recommended
Calcium Hypochlorite 2% 70° Good Good Poor Poor Fair Not Recommended Good Good Good Good Good
Calcium Sulphate Saturated 70° Good Good Good Poor Fair Good Good Good Good
Carbolic Acid CP 70° Good Good Poor Good Fair Good Good Good Good
Carbolic Acid CP Hot Good Good Good Fair Good Good Poor Good
Carbolic Bisulphide 70° Good Good Good Poor Fair Fair Good
Carbon Dioxide (Dry) 70° Good Good Good Good Good Good Good Good
Carbon Monoxide Gas 1400° Good Good Good Good Poor Poor Good Good Good Good
Carbon Monoxide Gas 1600° Good Good Good Poor Poor Good Good Good Good
Carbon Tetrachloride CP (dry) 70° Good Good Good Good Good Good Good Not Recommended Not Recommended Fair Not Recommended
Carbon Tetrachloride CP (dry) Boiling Good Good Good Good Good Fair Fair Poor Poor Poor Not Recommended
Medium Concentration Temp. °F 304 Stainless 316 Stainless 410 Stainless 416 Stainless 430 Stainless Nickel Alloy 400 Nickel Alloy C-276 PVC High Density Polyethylene Polypropylene FRP (Extren® 500/525)
Carbon Tetrachloride Aqueous Sol. 10% 70° Fair Good Poor Poor Fair Good Good Poor Poor Poor Not Recommended
Carbonic Acid 70° Fair Fair Fair Fair Poor Good Good Good Good Good
Chinosol Antis. Sol. 1-500 70° Good Good
Chlorascetic Acid 70° Poor Fair Poor Poor Poor Poor Good Fair Fair Good Not Recommended
Chlorbenzol Pure, Dry 70° Good Good Good Fair Fair
Chloric Acid 70° Poor Poor Poor Not Recommended Fair Good Not Recommended
Chlorinated Water Saturated 70° Poor Fair Poor Fair Good Good Good Fair Not Recommended
Chorine Gas Dry Gas 70° Fair Fair Fair Good Good Good Fair Not Recommended
Chorine Gas Moist Gas 70° Poor Poor Poor Poor Good Fair Fair Not Recommended
Chloroform Dry Gas 70° Good Good Good Good Fair Not Recommended Not Recommended Not Recommended Not Recommended
Chromic Acid CP 10% 70° Good Good Fair Fair Good Not Recommended Good Not Recommended Good Good Not Recommended
Chromic Acid CP 10% Boiling Fair Good Poor Poor Not Recommended Fair Good Good Good Not Recommended
Chromic Acid CP 50% Boiling Fair Fair Poor Poor Not Recommended Poor Fair Good Fair Not Recommended
Chromic Acid (Cont. S0₃) 50% Commercial 70° Good Good Poor Poor Poor Not Recommended Fair Fair Good Fair Not Recommended
Chromic Acid (Cont. S0₃) 50% Commercial Boiling Poor Poor Poor Poor Poor Not Recommended Poor Fair Good Poor Not Recommended
Chromium Plating Bath 70° Good Good Not Recommended Good
Cider 70° Good Good Good Good Good Good Good
Citric Acid 10% 70° Good Good Poor Poor Good Fair Good Good Good Good Good
Citric Acid 25% 70° Good Good Poor Good Fair Good Good Good Fair Good
Citric Acid 50% 70° Good Good Poor Poor Fair Good Good Good Fair Good
Citric Acid 10% Boiling Good Good Poor Poor Poor Poor Good Good Good Poor Good
Citric Acid 25% Boiling Poor Good Poor Poor Poor Good Good Good Poor Good
Citric Acid 50% Boiling Poor Good Poor Poor Poor Good Good Good Poor Good
Coca-Cola Syrup (Pure) 70° Good Good Good Good Good Good
Coffee Boiling Good Good Good Good Good Good Good
Copper Acetate Saturated 70° Good Good Good Poor Fair
Copper Carbonate Sat. Sol. In 50% NH₄oh 70° Good Good Good Not Recommended Fair Good Good
Copper Chloride 1% Aerated 70° Good Good Good Not Recommended Good Good Good Good Good
Copper Chloride 5% Aerated 70° Fair Poor Not Recommended Good Good Good Good Good
Copper Cyanide Saturated Boiling Good Good Good Not Recommended Good Good Good Good Not Recommended
Copper Nitrate 5% 70° Good Good Good Good Not Recommended Fair Good Good Good Good
Copper Nitrate 50% Boiling Good Good Not Recommended Not Recommended Good Good Good Good
Copper Sulphate 5% Aerated 70° Good Good Good Good Poor Good Good Good Good Good
Copper Sulphate Saturated Boiling Good Good Good Good Not Recommended Good Good Good Good Good
Medium Concentration Temp. °F 304 Stainless 316 Stainless 410 Stainless 416 Stainless 430 Stainless Nickel Alloy 400 Nickel Alloy C-276 PVC High Density Polyethylene Polypropylene FRP (Extren® 500/525)
Cottonseed Oil 70° Good Good Good Good Good Good Good Good Good Good Good
Creosote (Coal Tar) Hot Good Good Good Good Fair Fair Poor
Cyanogen Gas 70° Good Good Fair
Dichloroethane Boiling Good Good Fair Fair Poor Poor Not Recommended
Dinitrochlorobenzene Melted and Solidified 70° Good Good Good Good Good Not Recommended
Dyewood Liquor 70° Good Good Good Good
Epsom Salt (Magnesium Sulphate) Cold & Hot Good Good Fair Good Good Good Good Good Good
Ether 70° Good Good Good Fair Fair Not Recommended Not Recommended
Ethyl Alcohol 10% to 100% 70° Good Good Good Good Fair Good Good Fair Good
Ethyl Chloride (Dry) 70° Good Good Good Good Fair Fair Not Recommended Not Recommended Not Recommended
Ethylene Glycol Conc. 70° Good Good Not Recommended Good Fair Good Good Good Good Good
Fatty Acids 100% 70° Fair Good Fair Fair Fair Good Good Good Good Good
Ferric Chloride All Concentrations 70° Not Recommended Good Good Good Good Good
Ferric Hydroxide 70° Good Good Fair Fair
Ferric Nitrate All Concentrations 70° Good Good Good Good Good Not Recommended Good Good Good Good Good
Ferric Sulphate 10% to 50% 70° Fair Fair Fair Fair Fair Good Good Good Good
Ferrous Chloride Saturated 70° Fair Not Recommended Fair Good Good Good Good
Ferrous Sulphate 10% 70° Good Good Poor Poor Fair Fair Fair Good Good Good Good
Ferrous Sulphate 10% Boiling Good Good Poor Poor Not Recommended Fair Good Good Fair Good
Fluorine (Gas) 70° Poor Poor Poor Poor Poor Good Good Not Recommended Good Not Recommended
Formalin Formaldehyde 40% 70° Good Good Poor Poor Good Fair Fair
Formic Acid 5% 70° Good Good Poor Poor Good Fair Good Poor Good Good Good
Formic Acid 10% 70° Good Good Poor Good Fair Good Good Good Good Good
Formic Acid 50% 70° Good Good Poor Fair Good Good Good Good Not Recommended
Formic Acid 100% 70° Good Good Poor Poor Fair Good Good Good Good Not Recommended
Formic Acid 10% Boiling Good Good Poor Poor Fair Good Fair Good Fair Not Recommended
Formic Acid 50% Boiling Good Good Poor Poor Fair Good Fair Good Fair Not Recommended
Formic Acid 100% Boiling Good Good Poor Fair Good Good Fair Not Recommended
Fruit Juices 70° Good Good Good Good Good Good Good Good Good Good
Fuel Oil Hot Good Good Good Good Good Fair Good
Furfural 70° Good Good Fair Fair Not Recommended Not Recommended Not Recommended
Gallic Acids 5% 70° Good Good Good Good Fair Fair Good Not Recommended Good
Gallic Acids 5% 150° Good Good Poor Good Fair Fair Good Good
Gallic Acids Saturated (212°F) Boiling Good Good Good Fair Fair Good Good
Medium Concentration Temp. °F 304 Stainless 316 Stainless 410 Stainless 416 Stainless 430 Stainless Nickel Alloy 400 Nickel Alloy C-276 PVC High Density Polyethylene Polypropylene FRP (Extren® 500/525)
Gasoline 70° Good Good Good Fair Good Good Good Fair Good Poor Good
Gasoline 70° Good Good Poor Good Good Good Good Good Good Good
Glue Dry 70° Good Good Good Good Good Good Good Good Good
Glue Solution Acid 70° and 140° Fair Good Good Good
Glycerine 70° Good Good Good Good Good Good Good Good Good Good Good
Hydrobromic Acid Poor Poor Poor Poor Poor Fair Fair Good Good Good
Hydrochloric Acid All Concentrations 70° Poor Poor Poor Poor Poor Poor Good Fair Good Good Good
Hydrocyanic Acid Good Good Fair Fair Fair Fair Fair Good Good Good
Hydrofluoric Acid All Concentrations Hot and 70° Poor Poor Poor Poor Good Fair Fair Good Good Not Recommended
Hydrofluosilicic Acid 70° Poor Poor Poor Poor Fair Fair Not Recommended Good Not Recommended
Hydrogen Peroxide 70° Good Good Good Good Good Fair Good Good Good Good Not Recommended
Hydrogen Peroxide Boiling Good Good Good Good Fair Good Good Fair Good Not Recommended
Hydrogen Sulphide Dry 70° Good Good Poor Poor Good Not Recommended Good Good Good Good Good
Hydrogen Sulphide Wet 70° Fair Good Poor Poor Fair Not Recommended Good Good Good Good Good
Iodine 70° Poor Poor Poor Poor Poor Good Good Not Recommended Fair Good
Iodoform 70° Good Good Poor Fair
Kerosene 70° Good Good Good Good Good Good Not Recommended Good Good
Ketchup 70° Good Good Good Good Good
Lactic Acid 1,5, and 10% 70° Good Good Good Not Recommended Fair Fair Good Good Good
Lactic Acid 1% Boiling Good Good Good Not Recommended Fair Poor Poor Poor Not Recommended
Lactic Acid 5% Boiling Fair Good Fair Not Recommended Fair Poor Poor Poor Not Recommended
Lactic Acid 10% Boiling Fair Good Poor Not Recommended Fair Poor Poor Poor Not Recommended
Lard 70° Good Good Good Good Good Good Not Recommended Fair
Lead Molten 1000° Fair Fair Poor Poor Fair Not Recommended Not Recommended Not Recommended Not Recommended
Lead Acetate 5% Boiling Good Good Fair Fair Good Good
Linseed Oil 70° Good Good Fair Good Good Good Good Not Recommended Good Good
Lysol 70° Good Good Poor Poor Poor Good Good
Magnesium Carbonate All Concentrations 70° Good Good Good Fair Fair Good Good Good Good
Magnesium Chloride 1% and 5% 70° Good Good Poor Poor Good Good Good Good Good Good Good
Magnesium Chloride 1% and 5% Hot Fair Good Poor Poor Fair Good Good Good Good Good Not Recommended
Magnesium Hydroxide 70° Good Good Good Good Good Good Good Good Good Not Recommended
Magnesium Nitrate All Concentrations 70° Good Good Good Good Good Good Good Good Not Recommended
Magnesium Sulphate 10% 70° Good Good Good Fair Fair Good Fair Good Good
Magnesium Sulphate 10% Boiling Good Good Fair Fair Good Good

Considering All Movement in Pipe Support Design

September 26, 2017

By Angelique Geehan
December 21, 2010

Why consider movement in all three dimensions when choosing or designing pipe supports?

 

Movement, a major piping design consideration

Each component of a piping system has a job to do. Making sure a system can function correctly and efficiently requires that designers thoroughly account for each component’s design from the conditions at installation (cold) to those during system operation (hot). One requirement of pipe supports, critical to every piping run, is that they accommodate pipe displacement, or movement, generated during operation without adding excessive stress to the overall system. Movement results from changes in temperature, load, or any other operating characteristics that affect the forces at play — whether inside the pipeline or in the environment surrounding the system.

Movement can occur in all axes during a complete process or project cycle

Anticipating both the magnitude and direction of every possible movement during a process can be complex, but doing so is vital. If the pipe support design does not accommodate all movements properly, the finished system will likely deteriorate or fail.

Designers must always remember that movement can occur in three dimensions: axially, laterally (perpendicular to but in the same plane as the pipe), and vertically (usually parallel to the pipe support, in the plane connecting the pipe to the structural element). Failure to consider these movements could result in time-consuming and costly retrofitting or repair in addition to any labor and materials that might have been wasted, damaged, or lost. Also, designers must consider that any particular support might move more than would be reflected if only the starting and ending positions of components in a process cycle are examined. In other words, the extent of intermediate movements can and often does exceed the net movement.

Using pipe supports to accommodate movement

Pipe support assemblies can be classified according to both their level of engagement (active or passive) and function (load-bearing, guiding, or anchoring).

We designate support configurations whose primary capabilities are always engaged as active, whereas passive support configurations simply follow the movement of the pipe during normal operation. However, disturbances such as severe weather, impact, abnormal vibration or seismic events, will activate these otherwise passive supports, which then function as active anchoring devices.

Pipe support functions include load bearing, guiding, or anchoring. A load bearing support will uphold the weight of the pipe while allowing possible movement in all three dimensions. A guide will uphold the weight of the pipe while restricting movement in up to two dimensions. An anchor will completely restrict pipe movement in all three dimensions while bearing the weight, side, and thrust loads.

Active support components

  • Shoes: Used as anchors, bearings, and guides. Material used in fabrication usually matches piping material (e.g., carbon steel, stainless steel, chrome molybdenum or “chrome-moly”) and may also depend on operating temperatures.
  • Hangers: Used to support the pipe weight. Rigid hangers consist of components that do not permit vertical movement (in the axis connecting the pipe to the structural steel base) but do permit lateral or axial swinging. Spring hangers allow both vertical motion and either lateral or axial swinging. Hangers usually consist of a carbon steel structural attachment (e.g., lug plate, beam clamp), a carbon steel rod or rod assembly, and a pipe attachment (e.g., clamp, clevis, roller) fabricated of a material matching that of the pipe.
  • Struts: Used in either tension or compression to withstand a pipe force. The movement allowed is determined by the strut’s orientation (hanging, horizontal, or vertical). Consist of an end bracket connected to a clamp element (e.g., yoke, clevis) fabricated of carbon steel.
  • Sway braces: Primarily used to restrain forces other than that of the supported pipe weight. Part of the pipe movement can be accommodated by changing the orientation of the brace, as with a sway strut, with the sway brace spring coil allowing additional movement via compression and decompression. Usually consist of a carbon steel structural attachment, a carbon steel spring coil, and a pipe attachment fabricated of a material matching that of the pipe.
  • Customized supports: A category that includes project- or industry-specific components. Examples include custom-built frames upon which pipe will rest and multi-pipe channel assemblies. Sometimes called random hangers.


Passive support components

  • Snubbers: Used to restrain piping undergoing unwanted abrupt movement in one axis. Under normal operating conditions, snubbers simply “follow” the movement of the pipe, but when subjected to shock loading, the snubber, which can be mechanical or hydraulic, is activated and thereafter acts as a rigid restraint. The amount of stroke provided as part of the snubber design determines how much pipe movement is allowed under normal conditions.

Designers must consider that the above support configurations all allow some movement depending upon the overall size, orientation, and configuration of the assembly. For example, hanger assemblies can accommodate translational motion producing swing angles of +/- 4 degrees maximum. This means that designers may be able to accommodate greater pipe movement by incorporating longer support assemblies into the design, rather than introducing additional support components.

Pipe Support Movement of Four Degrees

When active and passive support assemblies, comprised of standard components, cannot meet specific system requirements, designers can add auxiliary components, which are designed to extend the range of motion that these supports can accommodate during normal operation.

Auxiliary components

  • Travelers: Used to translate the forces exerted on hangers, a type of active support, across horizontal planes in conjunction with the movement of the pipe. Single horizontal travelers translate forces across one horizontal plane; dual horizontal travelers translate forces across two planes. Consist of rectangular box with a lug protruding from the center and are usually fastened between the structural steel and the rest of the pipe support assembly. Usually fabricated from carbon steel.
  • Rollers: Used to translate forces at the support location on the pipe to a new position in the piping system. Consist of a rolling mechanism attached to the active support component; the other end can either be in direct contact with the pipe or connected via a saddle attached to the pipe. Commonly fabricated of carbon steel; fabrication with polyurethane reduces the overall weight of the component.
  • Slide plates (slide bearing plates): Used to reduce friction associated with axial and lateral movements. The reduction in the friction forces helps reduce stresses on  active support components during the pipe movement. Fabricated from carbon steel bonded to polytetrafluoroethylene (PTFE), 25% glass filled, for systems operating in environments cooler than 400 ºF. Can also use graphite, Bronzphite®, or marinite bonded to steel.
In real life: the consequences of not accounting for all movement in a process cycle

The following is an example illustrating the necessity of thoroughly reviewing all movements associated with pipe deflection during a given thermal cycle. In the initial (cold) position, a hydraulic snubber, attached both to stationary structural steel via an end bracket and to a pipe element via a three-bolt clamp, was installed at a cylinder position of 1 inch extension, with a total stroke available of 6 inches. An overall analysis indicated that the final operating (hot) position of the pipe would require that the snubber extend 4.5 inches (which could be accommodated by the remaining stroke of the hydraulic snubber cylinder).

After being put into service, the seals of the snubber were damaged, indicating that the cylinder, at some point, had been completely retracted or extended. Review of the pipe’s position indicated that it was correct according to the original design specifications.

However, a more thorough review of the pipe system revealed that, prior to reaching full operating conditions, the movement of the pipe created a condition in which the overall length of the snubber should have been reduced (retracted) by 1.5 inches. But, because the original set point of the snubber allowed a maximum of only 1 inch of contraction, the continued pipe movement stressed the snubber beyond its capabilites once it reached its fully contracted position (zero extension), thus damaging the support assembly.

Installed Position and Operating Position of the Snubber

To correct the problem, the original snubber was replaced with one that had an overall available stroke of 12 inches, allowing the initial set point to be increased to a cylinder position of 3 inches of extension. This new snubber design accommodated all pipe deflection throughout the entire process cycle.

Optimal use of pipe supports

•  Become familiar with Manufacturers Standardization Society Standard Practices 58 and any other industry- or company-specific codes that apply to your project, such as American Society of Mechanical Engineers B31.1 for power and B31.3 for process engineering (both of which refer to MSS SP-58). The manufacturer and installation team should also be familiar with these standards and how to accommodate any specific requirements that apply to your project.

• Collect and use good data: Know the full range of loads and movement the piping system will handle during a full operating cycle, and remember that movement in the real world occurs in all three dimensions.

• Make note of other factors that can affect piping loads, such as temperature, weight, states of matter, and external conditions.

How to Adjust the Load and Height of a Big Ton Spring Support

September 25, 2017

View our loading and height adjustment procedure for our big ton spring supports.

Big Ton Spring Supports Custom Designed for an LNG Facility

September 13, 2016

Big Ton Spring Supports Custom Designed for an LNG Facility

Type: Big Ton Spring Supports with PTFE Slide Plates
Size: 29-7/8″ x 29-7/8″ 16-1/2″
Material: Carbon Steel with HDG Finish | PTFE, 25% Glass Filled Slide Plate
Testing: Tested in a press connected to the load cell

PT&P custom designed big ton spring supports with PTFE slide plates for an LNG facility in Australia. The components within the spring housing include load columns, travel stops, spring coils and lifting lugs. Each assembly is designed for an operating load ranging from 16,276 lb. to 34,479 lb. and will allow for movement between 0.16″ and 0.24″. They are fabricated from hot-dipped galvanized carbon steel and measure 29-7/8″ x 29-7/8″ x 16-1/2″. The big ton spring support is ideal for applications that have very heavy loads with thermal expansion because of the stability they provide throughout the range of travel. These supports were tested in the press connected to a load cell to insure proper operation throughout the entire working range of the coils.

Big Ton Spring Supports Designed for Propane Dehydrogenation Facility

June 27, 2016

Big Ton Spring Supports Designed for Propane De-Hydrogenation Facility

PT&P custom designed big ton spring supports for a propane dehydrogenation facility in Texas. The components within these assemblies include the spring housing, load columns, travel stops, spring coils and lifting lugs. While both assemblies measure 42” x 24” x 26-1/2”, they were each modified based on independent specifications for operating loads and movement. The first will accommodate a load of 94,261 lb. and 0.085” of movement, while the second will accommodate a load of 102,219 lb. with 0.08” of movement.

This type of support is ideal for applications, such as pressure vessels, that combine very heavy loads with thermal expansion because of the stability they provide. The big tons were tested in the load cell to insure proper operation throughout the entire working range of the coils.

Big Ton Spring Supports

July 31, 2017