Mind the gas

Any way you slice it, petrochemicals are dangerous and must be treated as such. CLAIRE RENCKEN investigates gas hazards in the petrochemical industry.

Although flammable and toxic gas hazards are generally well understood by operators, technicians and safety personnel working within the petrochemical industry, continuous training and refreshment of knowledge is essential to avoid potential incidents linked to complacency or misguided actions. New personnel, who have received only very brief training in the basics of gas hazards and the operation of detection equipment, may be assigned work activities in potentially hazardous areas.

Flammable-gas detection equipment is generally designed to provide a warning of flammable risks before the gas reaches its lower explosive limit (LEL). The first alarm level is generally set at 20 percent LEL, with a second-stage alarm at 40 to 60 percent LEL. In some applications, such as gas-turbine monitoring, alarms may be set as low as five percent LEL.

Gases and vapours released from petrochemical processing activities can, under many circumstances, have harmful effects on workers exposed to them by inhalation, being absorbed through the skin, or swallowed.

People exposed to harmful substances may develop illnesses, such as cancer, many years after the first exposure. Many toxic substances are dangerous to health in concentrations as low as one part per million (ppm). Given that 10 000 ppm is equivalent to one percent volume of any space, it can be seen that an extremely low concentration of some toxic gases can present a hazard to health.

It is worth noting that most flammable gas hazards occur when the concentration of gases or vapours exceeds 10 000 ppm volume in air or higher. In contrast, toxic gases typically need to be detected in sub-100 ppm (0,01 percent) volume levels to protect personnel.

Prolonged exposure to concentrations above 50 ppm will result in paralysis and death. Gaseous toxic substances are especially dangerous because they are often invisible and/or odourless. Their physical behaviour is not always predictable: ambient temperature, pressure and ventilation patterns significantly influence the behaviour of a gas leak.

Hydrogen sulphide, for example, is particularly hazardous; although it has a very distinctive “bad egg” odour at concentrations above 0,1 ppm, exposure to concentrations of 50 ppm or higher will lead to paralysis of the olfactory glands, rendering the sense of smell inactive. This, in turn, may result in the assumption that the danger has cleared.

Definitions for maximum exposure concentrations of toxic gases vary according to country. Limits are generally time-weighted, as exposure effects are cumulative: the limits stipulate the maximum exposure during a normal working day.

However, it is important to note that, whereas portable gas-detection instruments measure and alarm at the time-weighted alarm (TWA) levels, instantaneous alarms are also set at the same numerical values to provide early warning of an exposure to dangerous gas concentrations.  Workers are often under risk of gas exposure in situations where atmospheres cannot be controlled, such as in confined-space entry applications, where alarming at TWA values would be inappropriate.

Workers, who face potentially dangerous situations, deserve the best protection available. Companies, such as MSA, build gas-detection instruments that can be relied upon by people across the world. These include the Altair 4X and Altair 5X portable gas detectors, among others. Devices such as these are used where multiple gases are a threat to employees. Altair 5X is a six-gas portable gas detector, with the advantage of having an internal pump, which is useful when working in confined spaces.

The instrument is used to check the working environment before it is entered by personnel. It is able to do this by bringing the gases in the environment into the instrument using the internal pump, a sampling line and a probe. This ensures that the user gets accurate readings of the gas, while still outside that environment, and therefore safe. If the environment is safe to enter, the employee can enter while carrying the Altair 5X or 4X, configured as per the suspected gas in the environment, or can wear the correct personal protective equipment (PPE), such as a self-contained breathing apparatus (SCBA). z apparatus (SCBA).

Safety + reliability = success

This year, courier and express parcel (CEP) specialist SkyNet celebrates ten years of exclusive partnerships in the petrochemical sector. It manages logistics for clients including Sasol, Engen, Total, Petro SA and Shell. Eugene Swanepoel, GM for SkyNet says: “We have second-perimeter access to some plants. To be allowed further into the facility than the first perimeter, we obviously have to meet stringent health and safety standards. We maintain the highest safety, health, environmental and quality (SHEQ) compliance, as well as International Organisation for Standardisation (ISO) and South African Bureau of Standards (SABS) accreditation.”

SkyNet’s sales and marketing manager: Africa, Diederick Stopforth, says the size of its footprint – and the efficiency this enables – is also a key to its growth in the field of petrochemicals. “There’s no question that safety is vitally important,” he says, “It’s a non-negotiable in this industry – or any industry moving hazardous substances. But once your accreditations and SHEQ standards are in place, coverage and efficiency becomes just as important.

“We’re currently running 74 distribution hubs – 50 in South Africa and another 24 around the Southern African Development Community (SADC) – and delivering to over 400 towns across the country daily. In fact, we opened new branches in Secunda and Three Rivers, Vereeniging, specifically to service our Sasol contract. You have to have a big footprint to be able to deliver everywhere: whether it’s to head office, the refinery, or a petrol station out in the sticks.”

Swanepoel adds: “When a client opens up a machine to find they have to replace a part and don’t have stock, they need a courier that delivers fast. And if they hit an unforeseen snag, which is out of their control, then communication becomes the key aspect in resolving the situation. During an unplanned plant stoppage – if something breaks down – speed and reliability is even more important.”

Furthermore, SkyNet is 45 percent black-owned and its broad-based black economic empowerment (B-BBEE) rating is now at level three. Stopforth explains: “Our four-year-old, owner-driver initiative does exactly what the B-BBEE codes (announced last year) intend, with respect to employment equity at management level. Rather than paying lip service, companies are going to have to take transformation seriously if they want to compete. So any CEP that ignores transformation simply isn’t going to get the work.”

Stopforth credits SkyNet’s expanding relationship with South Africa’s major petrochemical firms to its focus on the industry’s core needs: safety, reliability and transformation. Success in the CEP market, it seems, takes all three.