By Paul Bowers, Kevin Noakes and Clarence Wynter
“Process plant site safety — See that hole? Don’t fall into it”
Those two sentences almost sum up the safety instructions we were given some 35 years ago as a junior piping designer working in a refinery. Somewhat more important were the words, “Don’t touch anything.”
We were provided safety glasses (the nerdy type, not the cool-looking ones available today), a construction hat (white in color, so wrench-dropping pipefitters on scaffolding would have an easier target) and purchased our own steel-toed footwear. The scent of hydrogen sulfide (H2S) was in the wind, even at below 1 ppm in air, and piping designers would hang from and crawl on (sometimes icy) pipe racks like kids mountaineering on jungle gyms while juggling clipboards, measuring tapes, plumb bobs and pencils.
Hot water vapor hissed from steam traps, peculiar odors wafted by occasionally and unroped-off excavations for work on underground piping waited for a misstep or stumble. Workers clad in mysterious, head-to-toe white chemical suits and wearing Scott Air-Paks strolled to and from hazardous duty, causing many work trailer-housed, short-term contractors to wonder if they should be breathing filtered air as well.
Technical safety has evolved from a better understanding and quantification of hazards and has grown to consider all safety components as part of an overall safety system. Today’s process plant takes site safety more seriously and occupation-al health and safety in North America is prescribed by statutory code requirements of provincial and state authorities.
Twenty-five years of accident assessments of offshore production facilities, like Piper Alpha in 1988 with 167 fatalities or onshore plants like Skikda LNG production plant in Algeria in 2004 with 23 fatalities, have made assessing hazards part of modern risk-based plant design. This includes inherent safety design measures that attempt to remove hazards from the possibility of occurring by applying engineering best practices and protective safety measures in the event an accident does occur — for example, having safety shower and eyewash equipment nearby if safety glasses and/or Nomex® coveralls are not sufficient protection in an accident.
A typical process facility now provides initial orientation safety sessions for all visitors, even if visits are for short meetings, and requires more in-depth safety sessions for any personnel remaining on site for extended work periods. Visitor safety introductions can include muster point locations, gas/vapor cloud evasion, alarm familiarization, safety shower and eyewash station locations and operation, Nomex coveralls, safety glasses and hard hats. Plant site entry requires steel-toed footwear. These are usually the wearer’s own provision.
Site personnel are now trained in H2S awareness, first aid, emergency egress, ladder and platform safety and facility-specific procedures, the use of safety harnesses for climbing ladders and crawling in pipe racks, and the use of nonsparking tools.
Safety in design is continually evolving. For example, site safety apparel. Nomex fireproof coveralls are designed to protect personnel from exposure to fire and/or explosions. Working in gas vapor environments, where thermal flashovers due to volatile gases or explosions occasionally occur, Nomex coveralls can do the job and protect personnel and facilitate them reaching a safe place or muster point for first aid. However, wearing polyester clothing under the Nomex exposes a person to a high risk of obtaining first, second and third degree burns! With explosion temperatures exceeding 300 F, polyester attire breaks down and attaches itself to the skin. This causes a shrink wrap effect requiring hospitalization and burn unit treatment for recovery of a preventable injury. All personnel working in these risky environments must wear 100-percent cotton undergarments. Wearing required personal safety equipment, underwear included, reduces injury to yourself and your colleagues who will need to rescue you if you don’t.