Avoid Costly Flange Materials Mistakes

Gone are the days when most flange companies retain their own materials engineers/metallurgists or fabrication savvy personnel on staff. With the swings in the process industries over the past two decades, a number of flange companies have elected to dispense with their materials/metallurgy group and instead rely on a process engineer or a consulting metallurgist to specify materials of construction.

Process engineers are specifying welded equipment more and more, and often with a lack of fabrication/materials know-how. Their approach is to rely on a fabricator to guide them through the materials decisions and to point out any oversights.

Furthermore, with the widespread use of sophisticated vessel design software, many small- to mid-sized fabricators no longer employ engineers. Instead they depend on technicians to design vessels, many of whom lack the technical insight or materials background often required. In today's market, fabricators often do not have the time to challenge material/fabrication datasheet abnormalities and merely add these additional costs to their bid or choose not to bid, putting the engineer in a less competitive position. As a result, if the engineer receives a quote from the fabricator, it's weeks later, higher than expected, and with exceptions, deviations and surprises, all of which must be reconciled before proceeding. In the end, the project will have incurred unnecessary schedule delays, higher equipment costs, and then finds itself over budget and behind schedule before it gets off the ground.

You can pre-empt such problems with a bit of guidance. So, in this first article in our three-part series, we'll look at a dozen important factors to consider in materials selection. We won't get deep into the technical weeds but will provide pointers gleaned from our first-hand experiences that can help you avoid costly mistakes and delays.

Select the right material. For non-corrosive service, use design temperature to choose a readily available, cost-effective material. Table 1 offers a general guide [1, 2]. For corrosive or hydrogen service, consult a materials engineer.

Avoid specifying materials by trade name. Many projects involve replacement-in-kind of existing or similar equipment. The original design may have specified a particular brand or trade name alloy such as Hastelloy C276, Carpenter 20-Cb3, Monel or Inconel 600, and so these words are used throughout project development. Citing brand or trade name materials was necessary in the 1970s because many were unique and protected by patents. Today however, most major metals manufacturers produce their own and competitors' alloys. So, unless sticking with an exact proprietary alloy is mandated, using generic names, such as Alloy C276, Alloy 20, Alloy 400, or specifying the trade name “or equal” on the data sheet is more appropriate.

Take your bid expiration date seriously. Prices for commodity metals change daily on world metal exchanges. There was a time when mills/suppliers only adjusted their prices once per month and you could hold onto a firm quote for two to four weeks while it was evaluated. However, in recent years, metal pricing has become more sensitive to world events and more frequent and dramatic pricing swings occur. A fabricator recently reported that its quote for several large heat exchangers had to be adjusted upward $300,000 when the order was placed two months later — solely because of increases in stainless-steel tube cost due to a surge in nickel and molybdenum prices.

In today's market, fabricators must contend with material pricing from suppliers that can expire at the end of day. So, take your bid expiration date seriously. On the other hand, carbon-steel costs, while rising, tend to be less volatile than those of alloy steels; so it's safe to assume normal escalation during the project development/estimating phase.

Specify dual-grade stainless steel. There's much confusion about “L” grade, straight grade, and dual-grade 300-series austenitic stainless steels — in particular, Types 304 and 316. Engineers often specify lone “L” grade materials such as Type 304L or 316L on data sheets. The reason: during welding, such low-carbon stainless steels resist chromium carbide sensitization that can lead to preferential heat-affected zone corrosion in some corrosive processes. However, L grade stainless steels have lower strength than straight (non-L) grade stainless steels and the ASME code penalizes the design 15% to 20% with additional shell thickness and lower flange rating.

What's important to understand here is that a lot of the weldable forms of stainless steels (Types 304/316) produced today in the U.S. come dual certified as Type 304/304L or Type 316/316L. These steels have the higher strength of straight-grade stainless steels and have the superior resistance to sensitization during welding of the L grade stainless. This is because they're now made in a melt furnace process that substitutes nitrogen for carbon. Nitrogen strengthens the steel (like carbon) but won't promote sensitization during welding. Fabricators often will purchase dual certified materials but will use the lower strength values of the L grade material in their calculations if you specify L grade material on your data sheet.

Properly use corrosion allowance. This allowance adds extra thickness to account for uniform metal loss over the equipment's expected service life. The key word here is uniform. Mild carbon steel uniformly corrodes due to the galvanic cell potential of the interlaced ferrite-cementite grain structure, called pearlite.

Specifically, there are millions of anodic (ferrite) and cathodic (cementite) sites that in the presence of moisture provide the four necessary elements for corrosion (anode, cathode, metallic bridge, and electrolyte). Alloyed materials in aggressive service will also uniformly corrode because their strong protective oxide layer is breached.

This results in unnecessarily adding extra wall thickness and possibly crossing into a higher flange rating.

Learn About Sailboat Engine Gearbox Reconditioning in the Flange

One small problem we encountered was how to get the four coupling bolts back into their respective holes once in position. They had wriggled out after some difficulty when removing the gearbox and we worked on the premise that what came out must go back in. However, on re-assembly the angle was so acute, there was no way they would line up sufficiently to access the holes in the gearbox coupling flange from the forward engine side.

Well, as predicted, the best laid plans very often get interrupted - and so it is with our schedule for having the gearbox back into Patricks' yacht by this Saturday. Our gearbox expert Barry has completed the reconditioning and we have it back with us now. However, due to unforeseen circumstances we are unable to fit it this weekend and have put it back to Wednesday this coming week.

Barry, of 'Marine Gearbox Services' is one of the very few and fast disappearing doyens of marine gear box maintenance, repair and reconditioning. With many years of experience under his belt there is no marine gearbox that he doesn't know inside out (excuse the pun) and never comes up short. His knowledge on all things gearbox is profound and being very particular in his approach you will always be assured of the best, and have complete confidence in his work.

He showed and explained to us exactly what was causing the problem of the boat slipping out of and back into gear from time to time and what parts were worn and needed replacing. It is not the purpose of this article to supply a fully detailed manual of the work that needed to be done, suffice to say that friction clutch plates (sintered bronze) and steels were worn, the selector fork was too slack as was the selector ring. All these parts to be replaced along with the bearings, and all seals and gaskets. Any other parts Barry considered needed to be replaced as he worked through the job would be.

Believe it or not, the Hurth gearbox does actually contain all those parts. It is difficult to believe that (a) that many bits are required for a simple forward and reverse gearbox and (b) they all fit into that limited space. It was a wise decision on our part to take it to the expert and not attempt to dismantle it ourselves. We had a very informative time with Barry and on coming away we wondered what will happen when all the Barrys' of this world stop their work - a rare breed indeed. In the meantime however, Barry is fully occupied with this work and not planning on giving it up any time soon.

Having admired the re-conditioned gearbox with its brand new coat of paint from all angles and following several false starts (colds, 'flu and strong winds, big chop in a dinghy) Patrick and I find ourselves back on board and fully prepared to re-install the gearbox.

Hunkering down into position in the cramped space we prepare for the long haul of heaving the box (heavy when you are kneeling in a cramped position and leaning forward) onto the engine bolts and then getting all the nuts and washers on and tightened correctly. My suggestion of going on through into the engine, removing the bearings and checking them was met with astonished incredulity! - they had been replaced previously and were fine, so my brand of humour was treated with the contempt it deserved!

The only alternative (after much debate) was to bolt them up from the aft side with a spacer under the bolt head. This was tried on one, but as the lock nuts are half as thick again as the bolt head, we felt the clearance from the gearbox casing was insufficient - it was down to 1.5mm. In all probability this clearance was enough, but it looked way to fine for our liking and in its original position the clearance was around 3mm. What to do?

In the end it was quite simple - we obtained some shiny new locknuts which Patrick ground down on his workshop grinder, taking off 1.5mm from the underside.

Another dinghy trip out to the yacht saw us crunching down around the engine again and fitting the new nuts. Voila! they fitted perfectly, and with the additional spacer under the bolt head we now had 3mm. clearance between the nuts outer surface (the bolt end being flush with the lock nut) and the gearbox casing - looked much better, and along with peace of mind, it gave us confidence in a job well done.

All that remained now was to couple to the 'drive saver' and the shaft coupling and this was a breeze. The gear cable strut was then bolted back into position and the gear cable attached ensuring it was placed in its correct groove.

The moment of truth had arrived when it was time to start the engine and test that the gears would take up and operate correctly. With the engine on and running Patrick slipped it into the forward position - after a moments hesitation there was a satisfactory clunk and she was in gear - into neutral and into reverse - same clunk again and she was in reverse. Grins all round. Everything was working as it should so the kettle was put on and a sweeter cup of tea was never enjoyed more.

Patrick has just returned from a few days sail up the NSW coast and reports that when motoring the gears are working perfectly.

Lessons: With a little time and patience no job cannot be tackled on your own boat.

Never be afraid to consult with the experts - in this case it was Barry of Marine Gearbox Services.

When uncoupling the gearbox make sure you leave the four coupling flange bolts in position in the flange - this will overcome any problems when re-fitting.

Example of Seal Flange Types Under These Industrial Products

Seals are generally important in order to prevent leakages in products. When speaking of mechanical seals flange, expect that it is used in order to serve that very same purpose in plumbing systems. These devices are also highly favored in joining mechanisms together the same way that adhesives work. The device commonly contains pressure while getting rid of contamination in the process.

Mechanical seals work with the help of a rotating shaft. The housing of the seal works extremely well under different speed and temperature settings and is capable of withstanding the most extreme pressures. There are single acting and double acting seals. Seal types include induction sealing, adhesive and sealants and flange gaskets. Learn about these three through the following paragraphs.

Induction sealing

Also known by the name cap sealing, induction sealing is one that adapts a non-contact heating method. A metallic disk works on top of glass and plastic containers and the sealing transpires once the container is filled with the material and capped accordingly.

The most recent developments in induction sealing allows for the utilization of a foil sealed to the container. This eliminates the usage of a closure. The foil is either reeled or pre-cut and is placed and pressed down to the material. This activates the induction process thus bonding the seal to the container. This development is known as capless induction sealing.

Adhesive or sealant

A sealant is commonly described as a viscous material that has the capacity to change its state to a solidified form. This is used in order to prevent air, dust, gas, smoke and liquid penetration. The most common applications for seals include concrete and drywalls. Sealants are insoluble, corrosion resistant and have the best adhesive traits. Construction, aerospace and automotive industries benefit much from the use of these mechanical seals. Its main distinction from the adhesive is seen on the fact that sealants are not as strong as the other.

Flange gasket

Flange gaskets are mechanical seals that are used in order to provide a higher surface area to the sections of a pipe. They come in various sizes and are commonly bought depending on the diameter of the product. Included in the list of flange gaskets are sheet gaskets, spiral wound gaskets and ring gaskets. Sheet gaskets sometimes have bolt holes but in some instances they may operate without these holes. Spiral wound gaskets are those with stainless steel inner and outer rings. Ring gaskets are those that have different cross sections and are used in gas pipelines.

Circulator Pump Checking and Changing With Flange

To install the new pump, clean the old gasket material from the flange and install the new gaskets on the new pump. Carefully insert the new pump with gaskets into the flanges. Be careful not to damage the gaskets and pay close attention to the arrow on the side of the pump which shows the direction of the water flow. Make sure the new pump arrow is pointing in the same direction as the one you removed.

Then install the 4 bolts that hold the circulator pump in place. Tighten the bolts just so they are snug and not too tight. If they leak a bit you can always make them a bit tighter to stop the leak. Too tight may damage the gaskets. Hook up the wires to the pump motor again. Open the valves back up and check for leaks. Adjust bolts as needed. Apply power to the system and start the motor to check the operation of the circulator pump. The hot water should start to flow through the pipes and radiation to deliver heat to the house.

Circulator Pumps are the heart of a hot water heating system. Without the pump circulating the water, there is no heat. The very first thing you need to know is the water temperature in the boiler. If the water is hot, 140F or above, than the problem is not the boiler. It is heating the water. The next thing will be to see if there is power coming to the circulator pump. Either take the electrical cover off of the circulator pump motor, or check for voltage at the source of the wire going to the circulator pump. If there is no voltage, usually 110 volts for the US, then you have to look at why the motor is not getting power. I will do another article on that issue at another time.

So now we have established that you have power coming to the motor. There is hot water in the boiler however the pipes going to the radiation are cold. The next thing to look for, are zone valves. They are little motorized valves that open and shut to direct the flow of heat to different parts of the house or building. It is possible that one of them could fail and the circulator pump is running and moving no water. Usually the circulator pump will be making a noise and often be very hot if this is the case. Of course then you need to check the zone valve. That, we will also cover later.

Changing the pump is not always an easy process. I will attempt to explain some of the possibilities for changing out a circulator pump. First of all I would recommend that if you are reading this and you do not have an extra circulating pump in the basement beside the boiler. That you stop by your local heating and air conditioning supply house and buy one. For under one hundred dollars it will be cheap insurance.

If you had a responsible installer do your heating system, then you will have valves in the piping on either side of the circulator pump. These valves will isolate the pump from the rest of the system and changing the circulator pump will be fairly painless. If you do not have valves close to the pump, then you will need to find the valves that will be the closest to either side of the pump and close them. For some older installs there may not be any valves and you will have to drain most of the water out of the system to change the pump. This can get very complicated and professional help may be needed. The hardest part may be refilling the system and getting the air purged back out of the piping.

A very important thing you need to do to before changing the circulator pump, is to make sure that the electricity to the circulator pump motor is turned off. Verify that the power is off before touching the wires. The wires then need to be disconnected at the pump motor. Then the 4 bolts that hold the circulator pump in place need to be removed. Save these bolts, they may be needed to install the new pump. Carefully remove the pump from the flange. A pry bar or screw driver may be needed to break the pump lose from the old flanges. Be careful of the motor, depending on the type of failure, the motor can be very hot.

Some Press Brake Bending Techniques

Press brake bending is simple stuff: An arrow-shaped punch presses a sheet metal blank into a v-shaped die, thereby forming an angled bend. Or maybe, if we are getting adventurous, we could imagine something like a gooseneck punch making return flange, but that is stretching it as far as it goes, right?

No, not quite. Press brake tooling has come a long way in recent years, and can do a lot more than it used to, and probably a lot more than you think. Some of the more interesting techniques include wiping, rocker dies, 3 way bending and elastomer bending.

A wiping operation consists of more than one movement, unlike simpler shaping methods. A special die set is used, where the bottom die has movable elements. As the punch moves down and executes the first part of the bend, the bottom element receives the blank and is pressed down on its springs. This motion activates an element on the back of the die, which now moves in and executes the second part of the bend. A good example of the application of this technique is the making of a radiused return flange: The blank is pushed down on the first, springloaded element, and the resulting downward motion bends the blank to a right angle with a radius at the bending point. The second element then comes into play and finishes the job by folding the edge of the blank over, creating a return flange in the process.

Rocker dies are essentially simple dies - with a twist: The top die has a built in 1-axis joint, which allows it to enter a bottom die with a partially obscured opening. This makes it possible to form a channel in one pass, even if the flange is very long - something that (depending on the shape of the part)might not be doable in a traditional channel die set. In that case, rocker dies provide the benefit of reduced setup time and fewer operations in order to shape the part.

The term 3 point bending is used about a special type of die set, in which the bottom die has an element which can be adjusted in height by a servo motor. The top die is buffered from the ram with a special hydraulic cushion to compensate for little variations in the thickness of the blank. Together, the two dies make it possible to attain extreme precision in the angles bent - down to 0.25 degrees. This type of tooling is expensive though.

Elastomer bending is especially interesting. Here, the bottom die isn't steel, but a flat piece of synthetic material which serves to wrap the blank around the punch, as it comes down. The resulting bend radius will be very close to the punch radius, as there is little springback. Also, the elastomer pad does not mar or scratch the blank.

These are some of the flange techniques that keep press brakes relevant in today's sheet metal fabrication work.

The scale on the flange

The scale on the flange are specially desired for complex calculation, while the crystal can ensure maximum scratch protection and minimal reflection.

It is proved by many as a gorgeous timepiece to wear and enjoy with a exquisite yellow dial, a highly functional chronograph, a molded leather bracelet, crown and pusher. Its case design is highly regarded as a hallmark of the brand, which is made from polished stainless steel.

The Swiss are known for their fine movement and ability to keep time. The Panerai is greatly awarded in creating the most interesting and inspiring designs as well as the abilities to transform the luxurious and the kind of dignity you might feel with a watch on your wrist.

Among the various categories of watches, Ferrari Chronograph watch stands out as the best option for men.

The back of the watch is engraved with prancing horse and geometric pattern decorations, while the edges of the back is engraved the inscription-Engineered by OFFICINE PANERAI. The back is made of steel, while the strap is made of black leather and the inner side of the strap is made of yellow alligator leather. All these make the watch dazzled to the eyes.

If you are looking for a watch of high quality and superior elegance for yourself or for your boy friend, this watch would make a perfect present and will not let you down since the high quality and outstanding craftsmanship worth every penny of your money. The watch is not only accurate and reliable but also a great attraction that will draw many envious glances. So, do not hesitate now. Go and buy the best watch for you or for anyone else.

Diving function: unidirectional turning flange with divina time indicator.Thanks for the diamonds detail, the watch features a truly glamorous look. As for me, I mostly like the bright red rubber strap since it looks so lively and energetic. What about you? In a word, totally a luxurious sprorty design. Best functionality and fabulously designed for best style - I finally realize that why it could become the enduring fashion brand for so many years. What's your opinion?

Noise Canceling Review - Don't Buy the Klipsch IMAGE S4 Earphones

When you purchase these headphones you will get three different types of ear tips that you can wash. You get a small/medium dual flange design as well as medium and large single flange designs. These feel so light and narrow, you won't even know that they are your ears.

These Klipsch IMAGE S4 Earphones are really quite amazing. They are priced very affordable. These high performance earphones go way above and beyond what you would expect from the earbuds that normally comes with your Ipod or other listening device. As a matter of fact you will find these Klipsch headphones are way better than other brands- delivering superior quality, comfort that is second to none, superior musical accuracy, noise isolation, and bass.

Klipsch has figured out a way to take years of development and research to make the Klipsch IMAGE S4 even better while staying true to its audio heritage.

Amazing Fit and Comfort

These earphones have been made just for you, they have very flexible and soft oval ear tips that naturally fit the contours of your ear canal, providing you with long term comfortable wear as well as producing a perfect acoustic seal. A great earbud will minimize all of the outside noise, commonly known as noise isolation, and lets you enjoy your music at a lower, safer volume.

Premium Quality Sound

Every Klipsch product has over 60 years of audio expertise built inside. Klipsch is a leader in home theater sound and stereo and now a premium name in headphones.

Product Description

You can tune out the outside environment and tune into your own musical world with the Klipsch IMAGE S4 Earphones. These high performance earphones go far beyond what you would expect from a pair of earbuds. These noise isolating headphones deliver quality sound and comfort that is easy on your wallet.

Product Features

Oval Ear Tips for long-term comfort and excellent seal

High Quality Bass Response from dual magnet microspeaker and oval eartip seal

Stainless Steel carrying case with headphone organization

Three sizes of oval eartips (Small, Medium and Large) to achieve the perfect fit Piano black finish with chrome accents

The Pros

Great full sound with excellent bass

comfort: They come with a case and several different sizes of in ear plastic.

Noise Isolation: these earphones do a perfect job of isolating outside noises based upon the precise fit of the ear pieces.

Cord Length: not too long and not too short, just right.

The Cons

The Bass is not that strong

Noise isolation phones can be "uncomfortable" when you're out jogging or running making these phones great for stationary use.

cost $79.99 but really worth it.

Let's take a look at what a current owner has to say about it.

Pipe Flange Joint Poses Safety Concerns

A fuel gas pipeline in a pipe trench went under a road bridge inside a factory. A flange joint, fitted with a compressed asbestos fiber (caf) gasket, was located only 2.5 m from the roadway.

According to the area classification code used by the company there was a Division 2 area for a radius of 3 m around a caf joint and road vehicles should not be allowed unrestricted access to Division 2 areas. The factory wanted to open the bridge to unrestricted traffic.

Use secondary containment with a sensor

My recommendation is to leave the gasket alone for the reasons mentioned by the operations department. I would add a jacket around the flange and a sensor to detect if there is any leakage. The jacket would provide a small amount of secondary containment but would also concentrate any vapors so that the leak can be detected more readily. The signal should be transmitted to the control room and to a traffic light located at the bridge that signaled if travel on the bridge was safe or not. Since the flange has not leaked to date is a good reason to leave it alone but it does not insure that a leak won't develop in the future.

Properly dispose of the CAF gasket

The gasket may not develop a leak, but why play the odds? SAFETY FIRST! Replace the asbestos gasket with the spiral wound gasket. If the binding material is intact (not friable) remove it, clean and inspect flange surfaces, and dispose of the asbestos gasket according to regulations. If the gasket is friable it may be required to glove bag during removal by a supervised asbestos worker. Replace the studs and nuts with ferilium. Then do a wire wrap with injector cap nuts and valves attached. Inject sealant through the valves into the space between the wire wrap and the gasket. This will insure the flanges integrity and prevent a major spill in the off chance the gasket should fail. If the area is able to trap the gas in the event of a leak, a lower explosive limit (LEL) gas monitor should be installed with a warning signal if area gets above the LEL. This may seem a bit extreme, however all data are not available and more measures may be needed.

Rather than replacing the gasket, use one of the proprietary "gasket bands" that several vendors make. Some have the option with a grease zert to fill the flange gap with grease or other thixotropic material that would be pushed out under pressure. After applying this, a six-month visual inspection would tell if there was leakage from the pipe because the grease would be pushed out from under the flange seal. Provided the safety department, plant operators, and engineering personnel are all happy with the flange the classification of the area could be changed. The gasket replacement could then be deferred until a future "opportunity."

If the flange is under the bridge and it is a confined space, gas testing may also be required prior to entering under the roadway bridge; the safety department should be able to make this rule clear.

Chuck Stewart, sr. process engineer

BP America, Houston, TX

Which is the safest route?

We can shift the flange joint away from the road bridge, remove the existing flange joint, and make it a welded joint. This will require hot work to be done. But this is a one time job and it is the permanent solution. By doing this we will obey the codes and safety.

Keep Heat Transfer System Repairs Uneventful

Traditional heat transfer fluids (HTFs) and systems have been around for many decades. While much has been learned and written about the safe operation of these flange systems, less has been shared about the proper approach to making uneventful repairs.

The safe execution of repairs depends upon effective planning to protect against potential hazards. This article focuses on mitigating potential HTF-related hazards that could be encountered when repairing high-temperature organic HTF systems (those normally operating above 500°F). It is not intended to supersede any fluid-specific risk information available from the manufacturer, nor process or equipment-specific risk details associated with individual processes involved.

Every process has unique hazards associated with the chemical(s) being handled. Effective job planning and execution takes into consideration the hazards of both the processes and HTFs involved. The risks associated with HTFs can be divided into three primary areas: fire, human exposure and environmental exposure. The single, best source for fluid safety information is the material safety data sheet (MSDS) provided by the manufacturer.

Fire potential is typically assessed using flash point, fire point and autoignition temperature (AIT) data . Most of the commonly used HTFs operating from 500°F to 750°F, including diphenyl/diphenyl oxide (DP/DPO) eutectic fluid and the others listed in the table, have hydrocarbon chemistries. As such, they are typically classified as Class IIIB combustible liquids capable of igniting under the right conditions (fuel/heat/oxygen).

Depending upon the system design, operating environment, and fluid age and maintenance, some fire properties might become depressed below the values shown, which can increase fire risk. With awareness of these conditions, proper job planning can interrupt the hazard mechanisms and greatly reduce or eliminate the fire risk. A safe approach to fire prevention should include minimizing spark potential, inerting, conducting work while equipment is near ambient temperature, and insuring the area is cleared of hydrocarbon residues before beginning hot work.

Limiting the potential for human exposure to chemicals should be at the forefront of job planning considerations. Specific chemistries of HTFs will help define certain personal protective equipment (PPE) requirements, materials selection for fluid handling, etc. Review of the MSDS and technical literature will aid in the proper selection of PPE to avoid permeation of gloves or protective aprons, and could prevent failure of polymer components and other equipment resulting in a loss of containment.

The most common HTF-related injury is thermal burns. Whenever possible the system should be allowed to cool sufficiently to prevent burns from hot fluids or equipment contact when hands-on work begins. An additional benefit of cooling the fluids is reduced vapor pressure, thereby lowering potential exposure to fluid vapors.

Should non-routine material transfers be required, selection of hose materials, gaskets, containers, and O-rings/seals should all conform to manufacturer guidelines to avoid unexpected leaks, releases and physical contact. Ideally, job plans will incorporate these considerations, plus knowledge from industrial hygiene monitoring, to best determine the right combination of splash, face, eye, thermal burn, and/or respiratory protection required for each situation.

Exposure to the environment can also be safely managed by proper planning. Chemicals should be responsibly handled, but certain fluids might have regulatory restrictions that place stricter emphasis on environmental protection. This information should be provided in the MSDS.

During repairs, the bulk of the fluid should be kept properly isolated within the system designed for its containment, if possible. Any fluids that require removal by pumping, draining, blowing or other means should be transferred using equipment and materials fully compatible with the fluid chemistry. Any doubts about materials compatibility should be first resolved through discussion with a competent person knowledgeable of the fluid.

Additional preventive measures to protect the environment might include temporary dikes/curbs, drain plugs and absorbent media/pigs/socks. For fluids with high crystallizing points (e.g., DP/DPO), ensure that the piping is cleared of standing liquid to avoid possible failures due to expansion effects upon freezing. This can be done by draining low points, blowing lines with inert gas, and carefully opening low point flange, if necessary. Successful management of this component of the job will help prevent unnecessary clean-up work, disposal of fluid and recovery materials, and allow faster completion of the job, thereby minimizing downtime.

Make sure you’ve got a good flange match

The problem came in assembly. The 30-in. flange on the outlet of the first stage condenser didn’t mate up with the 30-in. inlet flange of the condenser. Rush orders were being made to get matching flanges and repairs.

The plant was adding a three-stage steam-jet ejector vacuum system. We would talk occasionally with the local vendor representative to make sure that the order was on schedule. Everything had moved along as expected and the entire system of equipment would shortly be ready for export crating and shipment to the plant.

Shortly before the shipping date, the rep called to ask me out to lunch, which was very unusual for him. He obviously wanted something but I wasn’t sure what. My boss told me to be less cynical and just enjoy a nice lunch. Lunch was nice and went well. Then the rep gradually approached me with a statement about a “little” problem with the vacuum system equipment. The purpose of lunch was finally out in the open.

The steam jet system had three stages with condensers after every stage. The condensers reduce the load to the next stage by condensing motive steam, any water vapor from the process, and process condensables. The first stage was designed with the ejectors directly attached to the first condensers. Three parallel trains were connected to a single seal drum (hot well).

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We wanted at least one complete ejector assembly put together in the vendor shop before shipment. This required the ejector manufacturer to get the exchangers and do the assembly. The ejector vendor’s preference was for each sub-supplier to ship components directly to our site. However, we pressed: “Just humor us, assemble at least one in the shop.” In the end, we reached an agreement to assemble a complete train.

The episode took place well before the American Society of Mechanical Engineers (ASME) began official efforts in 1980 to develop a uniform flange design for lines with 26 in. and greater diameters. Until then, two different flange standards were common: those of the Manufacturer’s Standardization Society (MSS) of the Valve and Fittings Industry, and of the American Petroleum Institute (API). The MSS-44 standard for Steel Pipe Line Flanges radically differed from the API-605 standard for Large-Diameter Carbon Steel Flanges.

Figure 1. ASME standard includes both Series A and Series B flanges.

Figure 1 contrasts the size and bolt layout for Class 150 raised-face flanges. They obviously don’t fit up. The ejector manufacturer had used one type of flange and its exchanger supplier had used another.

ASME sought a single unified design for nominal pipe size 26-in. to 48-in. flanges. Either MSS or API or both would have to change to create this standard. Neither would budge. So, today we have an ASME/ANSI standard that has two subsections. ASME B16.47 includes both a Series A equivalent to the MSS flanges and a Series B equivalent to the API flanges. For Class 150 and Class 300 (all sizes) and 36 in. and smaller in classes higher than Class 300, the Series A and Series B flanges aren’t compatible.

So while our problem occurred before the ASME standard existed, having a single standard hasn’t eliminated the issue. Occasional mismatches continue because of failure to correctly specify Series A or Series B. Few engineers appreciate that two potential flange types are available in large diameters. When you need a large-diameter flange, check what you have and make sure that’s what you are going to get.