The power of a vacuum (photo)
What happens when you try to pull water out of a tank using a 3HP pump and leave the vent closed… Membership Required You must be a member to access this content.View Membership LevelsAlready a member? Log in here...
Understanding why “bonding and grounding” may not be enough protection when handling non-conductive flammable liquids
In the world of flammable liquids processing, we have two (2) types of flammable liquids: Members can read all my articles on how these flammable liquids get classified as “conductive” vs. “non-conductive. This post is to explain HOW and WHY the traditional “bonding and grounding” used in the transfer of flammable liquids may be inadequate…...
Brittle Fracture (Catastrophic) Failure during HYDROTEST of Propane Bullet
I have posted numerous fatal accidents that occurred during the pressure testing of piping and pressure vessels. Although hydrostatic testing involves less energy release should something fail vs. using pneumatic pressure, the hazard(s) are still HUGE and must be respected. This incident involved a propane bullet built in 1994 and placed into service in 1996,…...
Why does OSHA’s 1910.146 require O2 to be sampled first?
Before an employee enters the space, the internal atmosphere shall be tested, with a calibrated direct-reading instrument, for oxygen content, for flammable gases and vapors, and for potential toxic air contaminants, in that order. We test for oxygen before testing for flammability (LEL) for two (2) critical reasons: Here is the breakdown of why this…...
Hydrostatic test of a cooling coil for an air-cooled heat exchanger fatality (OK-FACE)
A 43-year-old assemblyman died on May 26, 1999, from chest injuries he received earlier that day when struck by a high-pressure water jet emitted after the failure of a gasket during a hydrostatic test of a cooling coil for an air-cooled heat exchanger. At the time of the incident, the victim was part of a…...
Why can I add “Acid to Water” but NOT “Water to Acid”
The rule—”Add Acid to Water” (AA)—is one of the most important safety practices in a chemistry lab. It all comes down to how much energy is released when they mix and how the liquid behaves as a result. Let’s explore the science behind this safety rule together. I’ll ask guiding questions along the way…. Membership...
PRCS Fatality (Tanker Truck); 1 entrant and 2 would be rescuers
Employee #1 entered a semi-trailer truck to wash out the inside, which had contained a fatty acid (linseed oil). A short time later, he was found lying at the bottom under the hatch opening. Employees #2 and #3 jumped in to rescue him and were nearly overcome. Employee #1 died, and blood tests conducted two…...
How often do hydrostatic relief valves (HRV) have to be changed or tested?
The frequency for testing or replacing hydrostatic relief valves (HRVs) depends largely on the service environment, the fluid being handled, and the specific regulatory standards like OSHA, NFPA, CGA, or ASME governing your process. Because these valves are designed to protect against thermal expansion in liquid-filled lines—often in “blocked-in” sections—their reliability is critical to preventing…...
What is a process?
A process, in terms of Process Safety Management, is defined as: “Any activity involving a regulated substance including any use, storage, manufacturing, handling or on-site movement of such substances, or any combination of these activities. For the purposes of this definition, any group of vessels that are interconnected, or separate vessels that are located such that a regulated substance could…...
Fire Watch for your roofing contractor may have a 2-hr requirement
One of the debates we routinely have with fellow process safety professionals is the adoption of NFPA 51B vs. meeting 1910.252(a) requirements for their Hot Work safe work practice. I am a huge fan of NFPA 51B, as it is much more up-to-date than OSHA’s 1910.252, which, by the way, was based on the first…...
Massive Leak of Liquefied Chlorine Gas (Henderson, NV 1991)
A massive leak of liquefied chlorine gas created a dangerous cloud of poison gas over the city of Henderson, Nevada, in the early morning hours of May 6, 1991. Over 200 persons were examined at a local hospital for respiratory distress caused by inhalation of the chlorine, and approximately 30 were admitted for treatment. Some…...
Pressure/leak testing “closure welds” (345.2.3)
If we are making a final “tie-in” weld between two segments of pipe that have already been independently pressure tested, that specific weld can be exempt from a final system pressure test if:… Membership Required You must be a member to access this content.View Membership LevelsAlready a member? Log in here...