Recently I submitted my Certified Safety Professional (CSP) 5 year recertification summary to the Board of Certified Safety Professionals (BCSP). In addition, last week I taught two CSP preparatory examination classes to future CSP’s. The Certified Safety Professional designation is highly respected by the safety profession and indicates to other colleagues that you are at the top of the safety profession. Click here for information on becoming a CSP.
I am very please to announce I have finalized a triathlete sponsorship agreement with Lepera + Associates, PC – a San Francisco based law firm. This sponsorship will provide assistance as I prepare to join the world’s top athletes from around the globe to compete in the 2015 Escape from Alcatraz triathlon. Click here to see the press release. In November 2014, Jon completed the 1.5 mile swim from Alcatraz to San Francisco. Click here to see the video (video is at bottom of page.)
The 2015 Edition of NFPA 70E has been finalized. Significant revisions from the 2012 edition include:
• Elimination of HRC 0 moving all electrical work into arc rated clothing (non melting clothing required under AR clothing).
• New RISK BASED Assessment Tables with strong requirements for proper equipment maintenance.
• Elimination of PPE for all closed door operations
• Term HRC is gone. Clothing companies likely to start using ARC.
• Most ARC PPE in Tables is raised. No lowering for risk in tables.
• Calculations emphasized. Tables usefulness now limited and requiring less or much more PPE.
Click here to learn more about our November 7, 2014 course on the 2015 Edition of NFPA 70E.
I regularly conduct NFPA 70E training courses. Listed below are two questions that may enhance your understanding of electric arcs with respect to receptacles as well as residential homes:
1. Is there an electric arc flash hazard from a 120 volt electrical receptacle?
Response: A single phase 120V circuit would not really sustain an arc due to low fault current. The clearing time is very fast. That is why IEEE states not to calculate or be concerned on single phase circuits below 240V if fed from sources less than 125KVA.
2. What is typical short circuit current going from transformer to a residential home?
Response: Most transformers feeding homes are 25-50KVA single phase- 120/240V. These are generally low impedance transformers, but by the time the wiring etc. is considered, the fault current is in the 3000A range AT THE PANEL. The small #12 wire drops this quickly for branch circuits. Again, this is generally single phase, so the arc does not sustain past ½ cycle at this current and voltage level. This can still give a loud BANG like on a dryer circuit etc. if a plug comes apart. But the thing to remember is you are dealing with what would cause a second degree burn 18” away from the item basically instantly.
Trapped Under The Sea is an excellent book written by Neil Swidey that examines the 1999 Boston Harbor tunnel project confined space tragedy. Workers were required to descend 420 feet vertically into a tunnel and then travel 9 miles horizontally through the tunnel to perform work. Amazingly, the workers had to perform the work inside the tunnel with oxygen levels below 10% – clearly unsuitable to sustain human life. Everything had to happen without a hitch for the work to be performed safely. Unsurprisingly, several things went wrong leading to tragedy.
Click here for more information on this book.
On April 11, 2014 OSHA will publish the revised 1910.269 – Electric Power Generation, Transmission, and Distribution standard in the federal register. The effective date will be 90 days after publication. Among the changes, there will be PPE changes – specifically minimum requirements for eye, head, and face protection.
1910.146 (b) of OSHA’s Permit-Required Confined Space standard defines a hazardous atmosphere as follows: “Flammable gas, vapor, or mist in excess of 10 percent of its lower flammable limit (LFL);”. However, whenever I conduct onsite confined training courses for clients, I always recommend establishing a maximum of 0% LFL (or LEL). One exception is if the work task requires working with materials that emit flammable vapors, such as one of my clients whose technicians perform work inside underground storage tanks utilizing a styrene monomer. The rationale to my recommendation of 0% LFL/LEL is if your combustible gas meter detects any flammable vapor reading – some flammable material remains inside the tank. An additional reason is depending upon the calibration gas for your combustible gas sensor and the flammable gas vapor present in the confined space, the combustible gas sensor may actually be under-reading the actual concentration of the flammable vapor inside the confined space.
Consider the following example: A combustible gas meter calibrated on methanol is reading 10% LEL in a pentane atmosphere. To find actual % LEL pentane, use the following chart by Industrial Scientific. The multiplier is 1.9, resulting in an actual % LEL for pentane of 19%. This is above OSHA’s limit of 10% LEL.
To summarize, restricting LEL/LFL to 0% is the best practice. Whenever necessary to perform work emitting flammable vapors inside the space, purchase a sensor specific to the specific flammable vapor, if possible. Otherwise, utilize the applicable correction factor to confirm you are not exceeding acceptable LFL/LEL levels.
Electrically classified areas for flammable liquids (Class I), combustible dust (Class II), as well as fibers and flyings (Class III) require explosion proof electrical wiring within the classified area. You also need to be concerned about any workers who may attempt work using an unrated extension within the classified area. One potential solution from Lawson Electronics LLC is the EPEXC-25 extension cord. This cord is 25 feet in length and are equipped with a twist-lock design. For operation, the employee inserts the plug into a receptacle and twists until it locks into place. Click here for more information.
Over half of all electric arcs occur at 277 volts. There are a few reasons for this. One reason is 277 vac is a single phase circuit of a three phase 480 vac circuit. This circuit typically provides considerable fault current, in amps. A second reason is due to the fact that commercial and industrial lighting circuits are powered by 277 vac due to the fact that 480 vac are readily available. When qualified workers take such circuits for granted, mistakes and errors frequently occur.
To learn more about electrical safety, click here for information on my October 25, 2013 NFPA 70E course scheduled for Greensboro, North Carolina.
During a recent presentation on flammable and combustible liquids, I was asked about grounding and bonding requirements while dispensing flammable liquids with a flashpoint of 99 degrees Fahrenheit and below. Stewart R. Browne Manufacturing (770.993.9600) has an excellent document “Grounding and Bonding Applications for Control of Static Electricity” that describes (with illustrations) grounding and bonding requirements. With respect to maximum resistance with the grounding and bonding connections, Stewart R. Browne Manufacturing states the following:
“The design and installation of bonding and grounding systems requires careful attention that a continuous, low resistance path is established to remove charges from all parts of process equipment. The resistance of this path should be no more than 25 ohms to avoid static build-up to a dangerous level.” Click here to download the document (note: link is under grounding and bonding section).
Whenever grounding and bonding cables are installed they should be tested during initial installation, after repairs/damage to equipment, and at least annually with an electrical multimeter to verify there is no more than 25 ohms resistance between connections.