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Sodium Hypochlorite Valves And Piping
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Here is an excellent article about the practical containment and use of SH.

Important Considerations to Performance of
Sodium Hypochlorite Wastewater Treatment Piping Systems

 

by Kurt Lind, George Fischer, Inc.

An Adobe PDF version of this article is available by clicking here.
Click to get
Acrobat Reader.

Over the past 20 years, disinfection technology and chemical treatment for wastewater has been consistent with the use of Chlorine as the standard chemical to safely and effectively treat wastewater media. The delivery of the chlorine to the flow stream ranges from gaseous, liquid chemical, or carrier chemical agents. Today, through the development and realization towards improving safety and reducing risk, Sodium Hypochlorite (NaOCl) has commonly been used in various applications where disinfection or sterilization of water is needed. NaOCl is becoming more and more popular based on its inherent chemical characteristics of being a safer, less costly, lower risk chemical, and still effective means to treat waste water media. The problems and practical solutions for NaOCl and related piping systems are the discussion topics in this article.

Sodium Hypochlorite Characteristics

Sodium Hypochlorite can be considered a solution of dissolved Chlorine gas in Sodium Hydroxide. Simply put, its character is that of common household bleach or "swimming pool" chlorine; however, sodium hypochlorite for wastewater treatment usually is found in 12.5% concentration. Chlorine is easily released from the Sodium Hypochlorite due to the breaking of weak ionic bonds with its base molecule, Sodium Hydroxide. Piping material, valve selection, seal materials, pressure relief, and stagnation control, are a few design, safety, and operational measures to consider when designing NaOCl systems.

Sodium Hypochlorite carries a relatively high pH (about 12.8) and a concentrated chlorine gas element that again is easily released into solution. As the NaOCl is added, the solution becomes diluted in pH scale, but not by much. The solution of diluted water with sodium hypochlorite (12.5%) still has a pH of about 9 or higher. The reason behind this is due to the release of the chlorine and high concentrations of the caustic byproduct, Sodium Hydroxide. In some plants, various chemicals, such as lime or calcium oxide, may be added to help stabilize alkalinity of the media. This may cause problems with scaling inside piping systems thereby clogging up piping, interfering with valve operation, or making flowmeter and rotameter type equipment nearly impossible to read (see picture at right.)

Furthermore, outgassing occurs with sodium hypochlorite due to common decomposition of the chemical. Chlorine and oxygen are the most prevalent gases to consider when designing safety relief of piping systems or when making valve selection. Equipment used in piping systems must be carefully selected to withstand the high and fluctuating pH levels, outgassing concerns, and scaling effects. Chemical resistance, design safety, and system performance become major issues with respect to above.

PVC is the most widely used piping system material for sodium hypochlorite applications due to its good chemical resistance, availability and economic value.

Piping System Material Selection

For past years, PVC and CPVC piping materials have been used successfully for Sodium Hypochlorite applications. PVC is the most widely used due to its good chemical resistance, availability and economic value.

The biggest concern for PVC piping is the joint quality during installation. A few points to watch out for are:

  1. Strictly adhere to the material manufacturer’s joining procedures and also ASTM D2855 "Standard Practice for Making Solvent-Cemented Joints with PVC Pipe and Fittings." This is a very important factor as solvent-cement joining is sometimes taken for granted. Even leakage that isn’t seen by the naked eye will show up eventually if a sound joint is not made. Threaded joints should also be kept to a minimum and MIL spec P-27730A-rated Teflon tape should be used when making joints. Particular attention must be made when making the joint...each one.
  2. Good ventilation and Chlorine chemical resistant materials should be selected for NaOCl systems, especially in confined spaces like sheds, tank farms, pump houses, and the like. Over the course of time, chlorine gas will escape from the system causing corrosion problems for equipment and safety concerns for operating personnel in and around confined spaces. Anticipate leakage paths from joints and connections, granted you may not see them, but chlorine gas will find its way out. Larger leakage paths will be apparent with the formation of white crystallized salts forming around the leak port.

 

Valve Selection

Designing for valve selection over the past years has been discovered in some cases by trial and error. Today, we know to use caution with ball valves in Sodium Hypochlorite applications due to possible stem fractures caused by crystallization problems. Ball valves can explode due to excess gas buildup in the interstitial space of the ball valve while in the closed position.

In many cases, the downstream side of the ball has been machined with a small purge hole. This allows the interstitial space to "vent and wet" in order to avoid gas buildup or crystallization. In any case, ball valves should be cycled periodically to keep crystallization from occurring and to avoid stem fracture due to the ball "freezing up."

For Sodium Hypochlorite applications, true-union and flanged end diaphragm valves are recommended over ball valves due to their control capabilities, seal materials, durability, less maintenance, and longer life. PVC bodies are sufficient for choice of design with CSM (chlorosulfonated polyethylene - Hypalon - see picture at right) diaphragms and EPDM (ethylene propylene polymer) o-rings.

For sodium hypochlorite applications, spigot, true union and flanged end diaphragm valves, like the George Fischer Diaphragm Valve, are recommended over ball valves, due to their control capabilities, seal materials, durability, low maintenance and long life. This valve offers additional advantages with its snap-on handwheel and optional lock.

 

CSM diaphragms and EPDM O-rings

The benefits of using CSM diaphragm material is based on its good chemical resistance to Sodium Hypochlorite and Sodium Hydroxide (high pH) concentrations and its excellent mechanical properties like long flex life, tear and abrasion resistance, and toughness.

Other materials have been used in the past, such as FPM (Viton®) or PTFE (Teflon®) backed with EPDM or FPM. The lack of success of FPM to withstand concentrated caustic solutions and the expense of PTFE backed materials cannot compete with the effectiveness and added value considerations of CSM.

It may appear that EPDM diaphragm material would be adequate for Hypochlorite and Hydroxide applications from a chemical resistance standpoint; however, it does not stand up to the combination of properties CSM offers (mechanical, flex life, and chemical resistance). EPDM is more effective as an o-ring material due to its good chemical resistance and compression set characteristics for this particular application. CSM exhibits poor compression set resistance, thereby not making it a good material for static o-ring selection.

Measurement and Instrumentation

Instrumentation for flow and pH are critical for Sodium Hypochlorite applications. Measuring flow can be accomplished by use of a rotameter or by electronic means such as a vortex style flowmeters.

Rotameters can give both electronic and visual indication pending the need of the user. PVC connections, PSU (polysulphone) tube material, and EPDM o-rings are recommended. Again, consideration to scaling should be taken into consideration when selecting where to install the rotameter. A rotameter site tube that is "scaled" is nearly useless to visually measure the float position. Rotameters are effective instruments to measure flow in a simple and cost effective way, but can be problematic with respect to system scaling.

Another way to detect flow is to utilize a vortex style flowmeter. A vortex style flowmeter provides extremely accurate and reliable flow measurement with no moving parts. Essentially, it uses vortices created by the flow stream to measure the flow rate. It is relatively safe from becoming scaled and can be installed with remote and direct visual indication. Vortex flowmeters are highly accurate, reliable, but more expensive versus the rotameter type.

System pH instrumentation is also very crucial in order to monitor the concentration levels of Sodium Hypochlorite. The reaction rate of Sodium Hypochlorite increases by:

  1. the reduction of pH (releases more chlorine with reduced pH)
  2. higher Hypochlorite concentration
  3. higher temperature
  4. the presence of metal due to its volatile ionic chemical structure

Outgassing Considerations

Outgassing of chlorine and oxygen have been mentioned as concerns for system design. Gas buildup in the piping system Tank Transfer line, valves, and pumps is a topic for "design discussion". The consideration to design and system operation can be approached in the following:

  1. Stagnation of flow or system isolation has been one of the most noted operational problems with Sodium Hypochlorite systems. Why? When the system is stagnant or "not allowing gas to be circulated through the system," gas becomes trapped in the isolated system. The Hypochlorite will continue to outgas and will buildup extreme high-pressure if not allowed to vent or recirculate. Diaphragm pump ruptures, short run piping system and ball valve explosions, pump malfunction (airlocking), and gas pressure relief valves are a few sensitive issues in which to take precautionary measures. Generally, if a system is left stagnant for long periods, the system should be drained, flushed, or allowed to be bypassed through a recirculation line.
  2. Pressure relief valves and high point venting should be practically designed into strategic parts of the system with consideration to shutdown, service maintenance, and standard safety functions. Pumps, system isolation piping, tank piping, injection piping, and quality plumbing installation should be scrutinized. (See picture at right).

George Fischer V85 Pressure Relief Valve

Pressure relief valves and high point venting should be practically designed into strategic parts of the system with consideration to shutdown, service maintenance, and standard safety functions.

Conclusions

Investigate the elements of Sodium Hypochlorite and, surprisingly, don’t "over-engineer" your system. Be practical. Piping materials and components, pressure relief design, and standard operating procedures are of significant importance for optimum performance of Sodium Hypochlorite wastewater treatment systems. Explore the options closely when choosing the materials as what is presented as Sodium Hypochlorite may not be what to specifically design around. In retrospect with this examination of Sodium Hypochlorite, designing for the actual chemical "Sodium Hypochlorite" has been of short discussion. Sodium Hydroxide, Chlorine, and operational issues are the engineering considerations — caustic, corrosive, "neat and smart".

###

 

Kurt Lind is a Production Manager / Mechanical Engineer for George Fischer, Inc.,

2882 Dow Avenue, Tustin, California 92780-7285, (714) 731-8800, Toll Free (800) 854-4090

Fax: (714) 731-6201, e-mail: info@us.piping.georgefischer.com,

Internet: www.us.piping.georgefischer.com

 

Viton® and Teflon® are trademarks of E.I. DuPont, Inc.

All trademarks are properties of their respective companies.



-- Edited by Apple Roof Cleaning Tampa (813) 655-8777 on Saturday 18th of April 2009 08:12:11 PM

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This is great info, good find
The links and pics may be broke, but it may be the pc i'm using instead

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Baltimore MD Roof Cleaning 410-482-4367 wrote:

This is great info, good find
The links and pics may be broke, but it may be the pc i'm using instead




LOL - no the pics did not survive the journey biggrin

But the INFO did !

It is IMPORTANT to realize that SH is BOTH a Liquid and a GAS

This is why it wrecks compressors trucks laddrs and everything it touches.

 

 



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Yeah its tearing my van up as we speak lol


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Mine To!
One day I am going to be driving down the expressway and the bottom will fall out literally... Yikes!

What are we to do. Even if I purchase a new van it will eventually happen again somewhere down the line.

I have heard that vinager helps slow the effects,???

James
Exclusive Home Services
www.wecleanroofs.net

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Roof Cleaning Memphis TN wrote:

Mine To!
One day I am going to be driving down the expressway and the bottom will fall out literally... Yikes!

What are we to do. Even if I purchase a new van it will eventually happen again somewhere down the line.

I have heard that vinager helps slow the effects,???

James
Exclusive Home Services
www.wecleanroofs.net




OPEN the windows !!

 



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813 655 8777

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Hey Chris & CO,

Today was a good day.  Started off raining and stoped by 9:00AM More was forcasted on the way.  Heavy thunderstorms forcasted. I had about a 4 hour window to clean the roof on this 3500, single story home.  Front was ok. Not as bad as the back.  Finished in about three hours. I also sold the 250ft of wood fence. Finished and went back to the shop. Within the hour  the bottom fell out. Been raining ever sence. Good timing hu? I credit my speed to Surflow Pumps.... and time in service, 8 1/2 years.

Days like this remind me not to ever faint when the phones stop ringing.   Reminds me that they will ring again! blankstare

Darn I need an advertising sponser! Telling Ya Memphis is hot!

James
Exclusive Home Services Of Memphis
www.wecleanroofs.net



-- Edited by Roof Cleaning Memphis TN on Saturday 18th of April 2009 11:28:05 PM

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I have been using PVC and CPVC in building roof cleaning, soap dispensing and pressure cleaning systems for MANY years.

Many systems I have plumbed with these materials and have  not had ANY major problems.

PVC is a pretty decent material when fitted correctly, i.e. ends cut correctly, cleaned, and prep work done right. The cleaner and glue always needs to be installed properly.

Also Important: As mentioned in the DEFINITELY use an approved TEFLON Pipe Dope or TAPE on THREADED FITTINGS and BALL VALVES and ALWAYS were EYE Protection.

-- Edited by Roof Clean USA Georgia 229-227-0000 on Sunday 19th of April 2009 10:41:07 AM

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Have you guys thought about bedlining the inside of your van? It may cost $1000 but may be worth it in the long run....Just a thought

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Confident Roof Cleaning Houston TX wrote:

Have you guys thought about bedlining the inside of your van? It may cost $1000 but may be worth it in the long run....Just a thought



Always good opinions and info from you Scott,

Just my opinion but this is a good idea.. for pressure cleaners that do not keep much SH on hand.

Not so good for roof cleaners.

Why? Chlorine Gas and Liquid find a way to make even WIRING start to degrade,especially within ENCLOSED spaces such as vans or box trucks.

All Rubber parts not SH resistant will also eventually degrade include dash parts,wiring, chrome, even cloth or vinyl interiors.

Coating the ENTIRE INSIDE of a 1 ton van is not practical as it would be in excess of 1K to do properly, I know as I have had three estimates for our van some time ago.

As we thought it thru we decided to go in a different direction.

IMHO,

It is better to spend that $1000.00 on a certified welder and have him build toward  a SMALL (6x8 or 10) DOUBLE AXLE TRAILER that has brakes on both axles that can carry your tanks only.

Keep your TANKS and pump (if its an AODD) outside your van and WINTERIZE or remove and take indoors at end of your  SEASON on the trailer and hold the chemical gas at bay not contained during the summer heat inside, with your employees or yourself.

Not so good for your health and lungs.bleh


Carry your Cleaning agent OUTSIDE your Van and use a backup camera to help navigate.

Hope this helps.



-- Edited by Roof Clean USA Georgia 229-227-0000 on Sunday 19th of April 2009 10:58:01 AM

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Dave I agree 100%. I recommend to use an open trailer due to those same reasons. We use a 12x6 tandem axle trailer.

I am not familiar w/ the costs of the bedliners so that was a shot in the dark. Thanks for clearing it up.

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Confident Roof Cleaning Houston TX wrote:

Dave I agree 100%. I recommend to use an open trailer due to those same reasons. We use a 12x6 tandem axle trailer.

I am not familiar w/ the costs of the bedliners so that was a shot in the dark. Thanks for clearing it up.




A Trailer or a flatbed are what have worked best for us smile

 



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813 655 8777

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Apple Roof Cleaning Tampa (813) 655-8777 wrote:

 

Confident Roof Cleaning Houston TX wrote:

Dave I agree 100%. I recommend to use an open trailer due to those same reasons. We use a 12x6 tandem axle trailer.

I am not familiar w/ the costs of the bedliners so that was a shot in the dark. Thanks for clearing it up.




A Trailer or a flatbed are what have worked best for us smile

 

 



Scott of Confident and Chris from Apple are Right!

After years of trial and error Flatbed trucks seem to be the MOST versatile of all the builds I have seen and participated in.

I have a 1 ton Diesel E350 Cargo Van and and F450 1-1/2 ton truck for our needs. We also have a c30 van but it has some mechanical problems right now.

The vans BOTH have Heavy Duty hitches and bumpers and can hold ladders, scaffold, and still haul a SLIM, streamlined trailer for Roof Cleaning Agents ONLY. We send leave a long enough line with a Quick Disconnnect Ball valve so when we get to a job we just open the back doors, start the torpedo compressor and can run the AODD off the tanks and air regulator. The hose reel and pump reside in the van. We have a chemical mat inside with a aluminum chemical containment tray to catch  ball valve drips and QC connection mistakes.

In South Florida, there is a company called ICCES (Industrial Contractors Cleaning Equipment and Supply).

Though they have changed hands a couple of times over the years they still build some of the finest contract cleaning trailers, Van setups and flatbed setups I have ever had the opportunity to witness.

I learned a GREAT deal hanging out and talking shop with the fabricators when I would go buy parts or chemical for my roof and pressure cleaning back in the 90's.

They still make a "hell-a-va" consistant and quality product.

ICCES really advanced the roof cleaning trades back in the 1990's with a product that cleaned VERY well but had to be rinsed. It was called Revive-ALL roof cleaner.

 



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I LOVE the way flatbeds look. Here is my issue w/ flat beds. For just a regular size residential house, no problems because you can finish in 1-3 hours. But we do a LOT of very large jobs. Jobs that take 1/2 day - 3-4 days per project. And when noon comes around and it is lunch time, I can unhook from the trailer & go grab lunch & leave the crew to continue working.

If somehting breaks that i need to run to the hardware store for I dont want to have to roll up alll the hoses, take down the ladders, pull the tarps, basically break everything down and pack up just to run to the hardware store for 15 minutes.

That is the ONLY problem I can see w/ a flatbed.

How do you guys get around this problem, OR do the pros of a flatbed outweigh that problem?

I think for the PROFESSIONAL look, the Flatbed can not be beat.

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Confident Roof Cleaning Houston TX wrote:

I LOVE the way flatbeds look. Here is my issue w/ flat beds. For just a regular size residential house, no problems because you can finish in 1-3 hours. But we do a LOT of very large jobs. Jobs that take 1/2 day - 3-4 days per project. And when noon comes around and it is lunch time, I can unhook from the trailer & go grab lunch & leave the crew to continue working.

If somehting breaks that i need to run to the hardware store for I dont want to have to roll up alll the hoses, take down the ladders, pull the tarps, basically break everything down and pack up just to run to the hardware store for 15 minutes.

That is the ONLY problem I can see w/ a flatbed.

How do you guys get around this problem, OR do the pros of a flatbed outweigh that problem?

I think for the PROFESSIONAL look, the Flatbed can not be beat.




We BRING a Lunch biggrin

 

 



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711 Westbrook

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813 655 8777

See our website here 

Click here for more information

Here are more of our services

Watch a short video

 




 



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We bring lunch LOL

That was good

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Apple Roof Cleaning Tampa (813) 655-8777 wrote:

Roof Cleaning Memphis TN wrote:

Mine To!
One day I am going to be driving down the expressway and the bottom will fall out literally... Yikes!

What are we to do. Even if I purchase a new van it will eventually happen again somewhere down the line.

I have heard that vinager helps slow the effects,???

James
Exclusive Home Services
www.wecleanroofs.net




OPEN the windows !!

 



Besides you look silly driving down the road with your mask on.


A buddy of mine had just gotten back to Nashville after a trip and the old convertible top broke and would not go up. Yes you guessed it the bottom dropped out and it poured.

It just so happens that the trip they just returned from was a dive trip. They reached into the back seat and put on their masks & snorkels. When I passed them at a stop light I had to pull over because I was laughing so hard. You just have to know this guy, he is a total nut. Showed up at the office dressed a leprechaun for St. Patrick's day. (in honor of me LOL) Yes he is Irish.

 



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I just painted my van bed today with Rustoleum primer than white paint, hopefully doing this occasionnaly will slow down the rusting until I get the flatbed. I try to keep my tank empty and rinse out my van bed after every job.

James, I decided to donate my extra love at the end of the day to local churches, and also offer it to locals at an extreme discount. It should help to keep the van alive by keeping the tank empty and rinsed out.

Also my tank is already bubbling a little inside (probably not chemical rated just had it laying around) so I gotta keep it empty as much as possible.


Keeping my air compressor alive in there is another story, trying to get the new truck financed now.

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