By Jeff Cottrill
No matter what kind of work is being done, a worker always has to keep breathing. Sometimes, that can be difficult in an environment that is short of oxygen, or one in which the dust of harmful substances is present the air.
As workers in confined spaces can be vulnerable to either lack of air or dangerous gases, employers must provide proper respiratory equipment for each employee — whether that is a half-mask, a full-face mask or a more complex product with its own air supply — and it has to fit tightly and comfortably to remain effective.
“There are several reasons why workers may need respiratory protection,” says Daniel L. Curts, senior technical specialist with the personal-safety division at 3M Canada in London, Ontario. “The primary reason is, there is an elevated concentration of a gas, vapour or particulate due to the process the worker is doing, such as painting, cutting, welding, cleaning or demolishing items.” Some full-face protectors or hoods provide added protection for the face and eyes, he notes. “Several types of respirators have features that cool or heat the clean air, which can directly impact a worker’s productivity.”
The basic types
There two primary types of facial masks: the P95 and the more common N95. The P95 is designed primarily for welders, protecting workers from oil particles in fumes that can come from welding. Another option is a self-contained breathing apparatus (SCBA), which is used mostly by fire departments and other industries in which employees often work in confined spaces where oxygen may be in short supply. An SCBA, which includes a tank of air carried on a worker’s back and connected to a full-face mask or hood, is mostly intended for environments that are immediately dangerous to workers’ lives or health. Supplied-air respirators like SCBAs are also common in environments where workers do not know the full concentration of a gas, vapour or particulate.
Before an employer invests in respiratory protection, it is a good idea to take measures to deal with the risks of exposure in the work environment. Dennis Capizzi, outbound product-line manager for respiratory protection and thermal imaging cameras for MSA in Cranberry Township, Pennsylvania, suggests implementing an environmental-control device wherever possible.
“The first thing that any company should do is look into implementing environmental controls where possible, to eliminate or reduce the exposure,” Capizzi advises. If this does not bring the amount of contaminants in the air below the occupational exposure limit, it is time to select protection products.
“The first thing that the employer should determine is why they are considering the use of a respirator in their workplace,” Curts says. “The process starts with a hazard assessment and ultimately concludes with the minimum type of respirator needed to protect a worker in that environment.” The hazard assessment usually points directly towards the right kind of product to use, he adds. “Management may decide to utilize a higher level of protection because they may be looking for not only the health protection, but also increased productivity as well as cost savings.”
To ensure that respirators are working effectively, Capizzi points out, an employer should take several steps. “One is, obviously, understanding your environment,” he notes. “And testing the environment regularly to make sure that you understand the conditions that you are going into, should those conditions change at any time.”
As well, an employer needs to ensure that the workforce is properly trained on the environment and the equipment they are using to protect themselves from any contaminant that may be present. On top of completing medical and fit-testing evaluations, employers should also ensure that they have the proper clearances and that the chosen mask fits properly, Capizzi adds.
Until breath do us part
How long should a respirator last, and how often should cartridges be replaced? That depends on both the product and the work involved, according to Curts. “Most disposable respirators are meant to be worn for one shift,” he says. “In some situations, like a hospital environment, the company’s protocols dictate that the respirators be changed more frequently, depending on the biological agent that the workers may be exposed to.”
Some kinds of face pieces can last for many months or even for years, Curts adds. “However, the cartridges and filters typically have much shorter life expectancies. The cartridges’ service length is a function of the airborne concentration of chemicals, [a] worker’s breathing rate, relative humidity, sorbent material in the cartridge and temperature.”
As with many other kinds of personal protective equipment, regular inspections go a long way towards increasing the longevity of respirators. Capizzi recommends setting up inspection guidelines within the training modules of a Respiratory Protection Program.
“Before the user dons their respirator, they want to make sure that they inspect all components of [the] respirator for any cracks, tears, tackiness, missing parts, et cetera,” Capizzi advises. “If an inhalation or exhalation valve is missing, obviously, you want to tag that respirator for repair and replace it.”
A change-out schedule is required for mask cartridges, he adds. For example, using a certain type of cartridge in a particular type of work environment at a specific rate would necessitate a cartridge replacement after a certain number of hours. “Making sure that the user changes out those cartridges in a timely manner will help to ensure their safety as they move forward,” Capizzi notes.
In most cases, it is not practical or worthwhile to try to make cartridges last longer, according to Capizzi. “There is really not an effective solution, outside of removing a little of the contaminant or reducing the humidity in the room. Many times, making adjustments of this nature would take some serious investments, I would assume.”
Although respiratory masks and SCBAs are necessary for many jobs, they are not perfect protectors. For instance, even the most effective N95 mask designed for certain atmospheres allows a small amount of micron particles to permeate the mask when it is still brand new, before the dirt has built up to provide an extra filter. One needs to be really careful of the concentrations or whatever the hazard is.
Jeff Cottrill is editor of Canadian Occupational Health and Safety News.