SCBA - An Overview - Breathing Apparatus for emergency and industrial situations
Published: 01st Sep 2010
PPE is normally classified as either simple or complex in design - this is not a statement that I have ever particularly agreed with. In my mind, whatever PPE being used, it either offers the wearer protection or it does not - it’s really simple. In fact the whole aspect of personal protective equipment is simple: it either protects you or it doesn’t.
Products designed for respiratory protection are classified as complex PPE, although the levels of protection vary from protecting the wearer from basic airbourne dust to offering the wearer protection from chemicals, gases and other major contaminants.
Every once in a while emergency response workers are called to work in environments where the normal risks associated with their job descriptions differ. So when you look at fire-fighters, police, military and other services, it’s quite obvious what tasks they would normally be associated with. But in industry the risks may differ considerably, from rescue teams attending mining accidents, to fire teams working in industrial complexes or oil installations, for example.
Selecting Respiratory Protective Equipment
The whole thing about the selection of RPE (Respiratory Protective Equipment) in whatever form, is to look at the hazards the wearers will face. And it is vitally important that a full and thorough set of risk assessments is carried out. These not only look at the hazards that the wearers may face, but any hazard that may be caused by using the equipment. Both theses elements are critical not only for the successful use of the equipment, but also the wellbeing and safety of the user.
When you decide that it is necessary to purchase or replace your respiratory equipment, you need to ascertain what you actually need.
A lot will of course depend on how many users you have and the regularity and application you intend to use these sets in.
Self Contained Breathing Apparatus
There are lots of new innovations in the marketplace, and you may want to consider them, depending on the needs of the wearers and the type of usage that the SCBA (Self Contained Breathing Apparatus) may be subjected to.
The vision afforded by most facemasks is better than ever before. There is the option of telemetry, where you are able to monitor the user from a distance, particularly when they are out of sight.
In other cases you can even monitor the amount of air left in the wearer’s cylinder, and activate an evacuation warning signal from outside the building - you will see just how important this is when you read further on.
There are also adjustable back plates, which contour themselves to the wearer’s back, and can be extended or reduced in length depending on the height of the wearer and, importantly, taking into consideration female wearers. You can choose short or long duration sets, too, (which will have an affect on the weight of the set), offering wearers hands-free communications, purpose built into the facemask. This allows them to communicate with each other and gives them the ability to communicate with the controllers over a distance, greatly enhancing their safety and allowing the controllers to monitor what is happening at any incident, or anywhere the SCBA is being used. This is particularly advantageous where a wearer(s) may run into problems and request immediate assistance.
If you are a small organisation a lot of these features may not be of interest, and if your usage is small, my thoughts would be that simple is good.
Although I’m sure that all wearers will be trained in the use of the sets, unless there is a perpetual training regime in place, it would be easy for the users to lose familiarity with the product if the use is infrequent. In these cases, the most basic set would suit you best. I am familiar with all the major manufacturers of SCBA, and the basic sets they supply will do exactly what you want, and that is to deliver breathable air to the wearers.
Face Fit Testing
The other thing that you will also need to consider is Face Fit Testing. There seems little point in buying SCBA for your operatives if the masks don’t fit properly, or if there is severe leakage at the face seal - so each wearer needs to have a Face Fit Test carried out to ensure that a proper seal is achieved.
This may mean that you will have to purchase different sizes of masks, as you can appreciate, since the shape of people’s faces in various areas of the world are different, and this size variation is particularly relevant if some of your wearers are female.
So before you make any decision about the purchase of your SCBA, it would be wise to find out in advance if the supplier supplies face masks of various sizes. Please also remember that Face Fit Testing is not a one off occurrence, so should any of the wearers gain or lose weight, have teeth extracted, or anything that could affect their face shape, you have an obligation to retest them.
One other thing that has a bearing on the face seal is facial hair. It is advised that users do not have facial hair where the facemask meets the face. There seems little point in carrying out Face Fit Testing to ensure that there is a satisfactory seal at the face if you allow wearers to grow beards or side burns that have an impact on the face seal. Apart from breaking the seal, if there are airbourne contaminants, they may adhere to the wearer’s facial hair and then be transferred into the facemask itself. So if you have a wearer that has facial hair for any reason, they should not be considered as candidates for training.
The use of sets
Where are you going to use these sets, and how long do you need their duration with you to be?
These questions are very important. If you are using the sets in an industrial location which may have multiple levels, then one of the things you will have to consider is the weight of the set. The set may be worn by wearers of different ages, heights and weights, and if the sets are being worn in areas where a lot of climbing is required, the overall weight of the set would be a vital concern. Most short duration sets with cylinders afford the wearers around 30 minutes of breathable air. If you are using these sets in large or extended areas, a 30 minute set may suit as far as weight is concerned, but not duration.
If you look at sets that give you extended duration e.g. 45 or 60 minutes, the weight will be increased. I know in applications such as mine rescue, where long duration is required, normal SCBA is usually substituted by the use of Closed Circuit Breathing Apparatus, which gives up to four hours duration with a weight of around 15 kilos.
If you read the information supplied by most manufacturers with regards to cylinder size and duration, they will give you a brief overview of how long you can expect a set to last.
There are some things that you must consider when looking at this. If you can imagine a fire fighter, fully clothed in PPE working hard at an incident, you would be amazed at the speed at which they can drain an air tank. Consider the fact that they may have some distance to cover before they start to carry out any tasks at all. If the weather is hot or warm, this will also affect them.
Wearing heavy protective clothing in hot weather does increase the physiological loads on the wearers, and that increases the volume of air they require to function efficiently. If the wearer is a smoker (yes, there are still some of them around), then the requirement is even greater. So when considering the capacity of breathing air you must look at all these things. There are of course cylinders that will theoretically deliver an estimated 45 or 60 minutes.
When calculations are made to try and estimate the amount of breathing air available to the wearer, it is normally calculated on the wearer consuming approximately 40 litres per minute. So if you have a cylinder with a capacity of 88 cubic feet, convert that into litres by multiplying by 28.3 then divide by the wearer’s estimated consumption of 40 litres per minute, then you can estimate a duration of 60 minutes.
Studies of the effectiveness of RPE
There was a major study carried out in 2008, mainly covering the emergency services and high rise buildings. They used 33 men and three women aged between 30 and 53 years old.
One of things I don’t like about this kind of testing is the subjects used are normally checked out in advance, and are normally fit and healthy people. While this is fine when doing comparison testing, it is not all that realistic.
There are a large number of Retained (part time) or Volunteer fire-fighters in the UK or USA. Unlike the Wholetime or Career fire-fighters, who train on a continuous basis, they may only train once a week, and generally their levels of fitness may not be so high.
There was a telling statement at the end of the report which pretty much sums up my thoughts on these types of tests. It said that the wearers were asked to carry out these tests under non emergency conditions, with no smoke, no blackout conditions and no obstacles, and at their normal working pace.
The study was carried out only with professional fire-fighters who volunteered for it. It also identified that they chose relatively fit fire-fighters, declaring that they felt that less fit individuals would not have volunteered for the study and that larger, less fit individuals would have consumed 10% more air.
I have seen this kind of testing carried out so many times before, particularly when carrying out evaluations on garments, where mainly young and fit personnel have been chosen. Sadly this does not always reflect a good cross section of wearers, and the information made available is of limited use.
We don’t normally carry out our tasks in a controlled environment and rarely under ideal conditions. It has always been my opinion that any testing should be carried out in the most realistic but safe conditions, so we can monitor just how well the products actually work. Even with the subjects chosen, however, the results were very interesting indeed. Even working at the controlled rate they found at least 50% of the fire-fighters would have had their low air (that’s 25% left in the cylinder) warning sound activate between 11 and 12 minutes on a 30 minute cylinder.
That is quite startling, and also pretty much shows that the manual calculations carried out by the Entry Control Officer are just no longer accurate, and until we place equal importance on monitoring the wearers and their air consumption, it will always be a hit or a miss as to just when they should be evacuating the area they are working in.
Specification and evaluation
As such, you will appreciate how careful you must be when drawing up your specification, and that it is imperative to build in a safety margin for the wearer.
If you are a big user, one of the most important things apart from the specification you will have to undertake, will be the evaluation.
You need to look at the various scenarios and locations that you may have to use these sets in, draw up evaluation sheets and, most importantly, involve the wearers.
Look at the areas where there is the biggest likelihood of the sets being used and set up exercises using them. If you have experienced any problems with your current sets, the use of reception of communications, for example, go to the areas where you encountered these problems, so you can ensure any future purchases eradicate the problems that were identified.
Make sure you repeat the same exercise for every set that you intend to evaluate. I would also suggest that you select independent people to oversee the marking of the evaluation sheets. It’s not important that they have knowledge of the products. Indeed, there is an advantage in using people with little or no knowledge, as they will not be swayed by previous experiences of sets they have used in the past, or manufacturers that have supplied them in the past.
When we purchased our last SCBA we used the sets in the following areas that we identified as being the main areas of use.
The SCBA sets, telemetry systems and communication systems were tested in the following scenarios:
- Northlink passenger ferry (Aberdeen Harbour)
- Large shopping centre
- High expansion foam
- Confined space
- Ladder climbing
- Multi-storey dwelling
- Large department store
- Gas tight suits
- Hot fire training unit
While our evaluation of the sets was obviously within the context of firefighting, since this is my area of expertise, many industries where SCBA is used might also benefit from examining the criteria below.
Using career and non-career firefighters we set out to determine the following information:
1. During the evaluations, some of the areas assessed were (for the SCBA sets):
- Compatibility with existing PPE
- Ease of use
- Testing and maintenance
2. For the SCBA systems:
- Ease of operation (while wearing firefighting gloves)
- Battery duration (for radios, if applicable)
We attempted to replicate virtually every scenario that we may be involved in, to check for compatibility with other critical PPE and to look at the whole life costs based on maintenance during the projected life of the SCBA.
User acceptability is paramount, so the involvement of wearers during any evaluations is most important - after all, they are the people who will be using the product in earnest, and indeed in real time, their life may just depend on the performance of the SCBA.
The future looks bright, and there are some amazing things happening in the marketplace. In the United States, the International Association of Fire-fighters and the Department of Homeland Security have partnered up with a major manufacturer to produce a lightweight flat pack SCBA set. It eliminates the use of all types of cylinder and replaces it with a narrow and thin pressure vessel, reducing the weight of the set by up to 60%. This allows for far greater mobility and will help to reduce the physiological problems that can occur when wearing any kind of breathing apparatus.
Can you imagine the knock on effect using a new lightweight and compact SCBA would have on the users? The ability to extend the work duration without causing physiological stresses to the wearer would be fantastic in every way. The ability of the wearers to be able to manoeuvre and crawl into areas that have been previously out of bounds enhances the overall abilities of the users to carry out their tasks.
The materials that are available at this moment in the marketplace are also quite amazing - the volume and various types of co-polymers available is growing more and more, and the performances of these products are in some cases quite spectacular. While I am very surprised that it’s taken so long to look at this new technology, there are reasons why.
A large cylinder sticking out your back has always been regarded as a potential danger, particularly when attempting to work in restricted areas. I would imagine that if every time a wearer got hooked up, or was hindered by the bulk of the cylinder on their back, if this was recorded as a near miss, I bet they would run into the hundreds, perhaps even the thousands.
Of course there are really three reasons why there has not been so much innovation in the marketplace. The cost of developing a new system with new technologies that are available are quite onerous for any manufacturer, and I can understand that manufacturers would be reluctant to spend lots of money developing new sets without a ready made market to sell in to.
The other thing is the reluctance of the buyers to embrace the new technologies that may be made available. There has always been the kind of attitude that says “that’s how it’s always been; it was good enough before, so it’s good enough now.”
Procuring Breathing Apparatus
The final consideration, of course, is cost. Sadly there is still a camp that buys based solely on the cost of the items that are currently available.
I do not criticise them for that. Where you may have to convince those who hold the purse strings that there are advantages to embracing the new technologies, I know from my own experience that this is easier said than done.
Not everyone puts the protection of the wearers at the highest level when it comes to procurement. In today’s difficult times, where the bottom line is getting lower and lower, those tasked with procurement are making decisions based on many things, and sadly safety may not be the highest priority on the list.
I hope that there is continuous work carried out on these new and exciting innovations, and that all the major manufacturers play a part in them. There are some excellent manufacturers and once they get involved in these new and exciting projects, I believe everyone will benefit from it.
Exciting times lie ahead. Watch this space.
I have worked with Grampian Fire and Rescue Services for 30 years and am currently Research and Development Manager. My specialties are in Firefighters Personal Protective Equipment, and have been involved with these specifications for the last 25 years. I am a committee member of four British standard committees. I am coming to an end of an excellent career where I have had the privilege of protecting Firefighters.
Ian S Moses Research and Development Manager Grampian Fire and Rescue Service 19 North Anderson Drive Aberdeen AB15 6DW Scotland United Kingdom
Tel: +44(0)1224 788690
Mob: +44(0)7967 357569
Published: 01st Sep 2010 in Health and Safety International