How NOT to Install a Water Filter

We recently investigated the cause of failure of a water filtration unit that cracked and caused an extensive amount of water damage to residential dwelling.  During the course of the investigation, it was determined that a whole house water filter unit had been installed in a cabinet beneath the kitchen sink.  This location is perfectly acceptable as were the piping connections that were made to connect the unit to the cold water supply line.  However, when the upper and lower halves were assembled, the pieces were put together with pipe joint compound.  This is absolutely unnecessary and amounts to an improper installation.  The filtration unit comes with an O-ring that is intended to fit between the halves and seals any gaps while preventing water leakage.  Although the unit failed as a result of over pressurization,  the presence of pipe joint compound indicated that the filtration unit had been improperly maintained.  The failure of the unit is shown in the photographs below.

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Continuing Education Update

We just completed a seminar on steam system design.  The course covered such topics as sizing steam valves, traps and pilot valve applications.  The course also covered piping distribution as well as load balancing.  Following accepted design practices is as important as correctly sizing the components that make up the system.  With more concern placed on the conservation of energy, the time when ignoring energy waste has come and gone.  More and more energy codes are being adopted by states in an effort to curtail energy waste.  Tennessee, for example, follows the International Energy Code.  As a result, architects and engineers can be held responsible for not following proper procedure as outlined in those energy codes.  More importantly, architects and engineers can be sued if their designs do not perform as building owners expect.  It then follows that insurance carriers that provide errors and omissions coverage for architects and engineers have to pay for designer’s mistakes.  Those of us that practice in forensic engineering will be looking for deviations from code requirements as well as accepted design practices.

 

 

The Problem With Oxygen Depletion Sensors…

The problem with oxygen depletion sensors is that they don’t sense oxygen.  Oxygen depletion sensors (ODS) are found on gas log appliances and are intended to shut the appliance off before the oxygen in a space falls to a dangerous level.  ODS sensors are thermocouples which produce a millivoltage when heated.  For this reason, the sensing end of an ODS sensor should be in contact with the pilot flame.  When operating properly, the flame heats the thermocouple which produces a millivoltage which in turn keeps the main gas valve open and allows gas to flow to the main burner.  When the flame cools as a result of low oxygen levels, the thermocouple or ODS fails to produce the necessary power to keep the main gas valve open and allows it to close, preventing gas flow and subsequent ignition.  The real problem however, is not low oxygen level, but the production and distribution of soot.  Anyone who has ever dealt with a soot damaged home knows how difficult the process can be to recover from the damage.  You see, appliances that burn with a yellow flame are already burning natural or propane gas incompletely.  That is, the carbon not consumed by the combustion process, will be visible and deposited as soot on clothing, furniture, draperies and appliances.   As a result, the ODS will NOT shut down the unit in time to prevent a soot production problem.  The lesson to be learned here is that even though your appliance has an ODS, don’t be fooled into thinking that you are protected.  Remember, if your appliance is designed to burn with a yellow flame, it is already producing soot.  Keep an eye on your fireplace insert, particularly if yours is unvented.  You will eventually see soot on the inside walls and if you see it there, it’s in the house!  The only way to prevent further damage is to quit using the gas logs set.

 

What’s Wrong With This Picture?

In a recent investigation of a crane outrigger failure, we were provided with some photographs of the incident by the insured company’s personnel.  At the time of the outrigger failure, the insured company was attempting to lift crawler tracks for attachment to a 120 ton crane using a 40 ton boom truck.  It was understood that the weight of the tracks was 26,300 pounds.  However, as soon as one track was lifted off the ground, the left rear outrigger buckled.  From all indications, the load was under the load limit capacity of the boom truck.  Upon reviewing the photos that were taken by the insured company, and specifically the area where the buckling occurred in zoom mode, it was noted that the outrigger failed at the point were it exits its storage enclosure.  Upon further inspection of the photograph, something very unusual was noted.  Can you tell what it is by looking at the picture below

Give up?  If you look to the left of the area where the outrigger buckled you will see that the rear end of the large crane is resting on a part of the bed of the boom truck.  In the original photograph provided by the insured company, the position of the large crane on the boom truck bed, is not obvious because it was taken at a distance of several feet away from both vehicles.  The question then arises as to whether the view could have been distorted because of the angle of the photographer as they took the photograph.  The answer is no.  As it turned out, the insured company also provided additional photographs which documented the position of the large crane on the bed and after it was completely removed.  Unfortunately, those photographs cannot be published because they can identify the insured company and therefore, constitute a privacy issue.  Suffice it to say that the partial load of the large crane was enough to cause the outrigger to buckle when combined with the track load of 26,300 pounds.

What’s Going On?

Just completed an investigation into why the mast of a rock drilling machine came crashing down on the machine with no warning.  If you’ve ever seen a rock drilling machine, they are equipped with a mast that rests in a horizontal position and can be raised into a vertical position for drilling.  In this particular case, the mast was in the process of being lowered when four bolts failed at the pivot points where the mast rotates from the vertical to horizontal.  Looks like it was just one of those unfortunate things that happens.  Currently conducting an investigation into why the electrical system in a cement mixing truck appears to have short circuited and burned some of the wiring.

More on the Use of PEX Pipe

I just completed watching a webinar on “Designing Effective PEX Hydronic Piping Systems”. I have written on the subject of PEX piping before (See “The Problem with PEX Pipe” published 7/21/2012 and “Update – The Problem with PEX Pipe published 1/9/2013) and as a refresher, PEX stands for cross-linked polyethylene.  This is a chemical process whereby pipe is manufactured by cross linking elements of the molecules that make up the material.  The resulting pipe definitely has some advantages in terms of price and handling.  However, no matter who the manufacturer is, the pipe still has two major drawbacks: it is affected by UV radiation (sunlight and similar lighting) and it is made brittle by chlorine.  In the case of hydronic systems, these are systems that carry cooled or heated water for cooling and heating purposes, mostly found in large commercial and office buildings.  These types of systems don’t carry potable water and as a result are not susceptible to the deterioration caused by chlorine.  Since the piping is usually hidden, it is also protected from the effects of UV radiation.  The concern arises when PEX piping is used in plumbing applications to carry potable water to any end user.  Chlorine can and will attack the pipe and cause it to eventually leak.  Water leakage, depending on the location can result in property damage costing thousands of dollars to repair.  Some manufacturers use antioxidants to neutralize the effect caused by chlorine but, it can be “used up”.  That is, when the antioxidant effect has been depleted, chlorine will continue to attack the pipe as if the antioxidant were never there.  Uponor, the sponsor of the aforementioned webinar, has been contacted and questions submitted for their response but, we have not yet heard back from them.  If Uponor responds after this article is published, then we will pass along their comments.

This is What Can Happen When the Sprinkler System Doesn’t Work…

The previous post on fire protection systems training talked about systems and the importance of maintaining that equipment.  The following describes one instance and the consequences if the sprinkler system isn’t operational.

On December 1, 2008 a warehouse building, located in Dyersburg Tennessee and owned by the Bekaert Corporation, was destroyed by fire. The building complex is shown in the photo below.

 

The wing on the left was the side that was completely destroyed. At the time of the fire, the warehouse had been leased to Briggs and Stratton for storage of their lawn mower products.  It was later determined that Briggs and Stratton lost approximately $25,000,000.00 in inventory.  When the lease was signed, one of the clauses stated that Briggs accepted the building in an “As Is, Where Is” condition.  It also required Briggs to make any repairs required by codes to bring the building into compliance.  Codes, in turn, required that Briggs obtain a certificate of occupancy prior to moving into the building – neither of which were done.  (Our involvement in this investigation was as a codes consultant.)  Briggs moved in to the building, brought in their products and stacked them to the point where the use of the building would have been classified “High Piled Storage”.  For over one year, the building contained products that were put at risk by the manufacturer, Briggs and Stratton.  When the investigation into the fire had been completed, there were some differing opinions as to the cause of the fire.  However, most of the discussion was centered on a metal halide lamp and a bulb that possibly exploded.  Because most of Briggs’ products were stacked above 12 feet, the explosion of a metal halide bulb could easily have ignited combustible material, ie, pallets wrapped with plastic. With no sprinkler system in operation, there was no way to stop the fire in its initial stages.  As a result, the building and all its contents were destroyed.

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