Covid-19 is making oxygen management crucial for hospitals

The current Covid-19 pandemic is pushing healthcare to the limit – but oxygen management in hospitals has become a particular challenge for health systems worldwide. Within the healthcare environment, the safety of the healthcare providers and their patients is paramount.

When patients are hospitalised with Covid-19 they often need additional oxygen, and the logistics and sheer volume of this demand is forcing hospitals to take drastic action to manage oxygen use.

A recent BBC documentary, for which a film crew traced the impact of Covid-19 on the Royal Free Hospital in London, clearly shows how the problems of oxygen management are taxing front-line medics and NHS managers, and directly affecting patient care.

At the time of filming, 80% of patients at the Royal Free had Covid-19 and most were on supplementary oxygen at between five and thirty litres per second. As Rui Reis, operations manager for estates at the trust, explains in the film, the hospital used a month’s supply of oxygen in two days and was faced with the prospect of drops in the pressure of patients’ oxygen and in delivery levels – with potentially catastrophic results.

In more normal times, the hospital’s estates management could act to mitigate the problem. But all such actions would require a 4–6-hour shutdown of the oxygen supply.

And in a pandemic, that simply is not an option.

Striking a Balance

The Royal Free had never experienced such oxygen issues before, and soon realised that a balance had to be struck between reducing oxygen use and simultaneously maintaining patient care and the oxygen infrastructure. As a result, they took various measures, for example doctors decided to reduce target blood oxygen levels from 92–94% to 90–94%, while giving clinicians the option to increase oxygen levels in line with patient need. And operations director Rachel Anticoni ensured that every oxygen outlet was closed off where possible to avoid leaks, rather like stopping a dripping tap.

In the film, Rachel Anticoni reports their solutions had reduced oxygen use by around 3,000 litres per minute.

Gas monitoring makes the difference

The Royal Free offers a fine example of how good gas management can improve outcomes and operations. This is something that Crowcon knows about, because we already supply hospitals with our oxygen detectors – these provide early warning of  oxygen-riched environments (which can be an explosion risk) and can also be used to detect the leaks that drain oxygen capacity.

To summarise:

  • The Covid-19 pandemic means that hospitals must now use unprecedented amounts of oxygen.
  • This has caused them to struggle with capacity and mitigate against unnecessary use to ensure supplies are sustainable.
  • Crowcon oxygen detectors can help, by warning hospitals of oxygen leaks and preventing the occurrence of oxygen-rich environments.
  • In this way, gas monitoring protects health system resources and patients alike.

Find out more about Oxygen risks in healthcare environments in our infographic here.

If you want to know how we can help with monitoring oxygen use to ensure supply or prevent oxygen rich environments pose an explosion risk, our experts can help, please get in touch.

Are you safe to re-start operations?

As governments around the world ease lockdown measures that were introduced to combat Covid-19, many of us are starting to plan how to return to business. But re-starting operations after a break can present specific gas-related problems and dangers that must be dealt with before operations begin.

A terrible example of what can happen otherwise has recently occurred in India. There, a persistent styrene leak, from a factory that had been closed due to the Covid-19 outbreak, killed at least 11 people, and harmed many more within a radius of several kilometres.

The need to check gas safety after a break in operations applies across many sectors. These include:

-Car plants

-Manufacturing facilities of all types

-Bars, restaurants and hospitality venues

-Leisure centres and swimming pools

-Refineries and chemical processing plants, where operations have been scaled back or stopped due to reduced demand

-Laboratories

-Schools and colleges

-General industrial sites that ceased operations due to Covid-19.

What are the dangers?

While the challenges arising will vary by sector, the most common include:

  • Re-pressurisation of systems. Many industries – from schools and colleges to bars and oil refineries – use pressurised systems or equipment such as boilers, steam heating systems, autoclaves, pipework, heat exchangers and refrigeration plant. If these are not correctly pressurised, they may explode, leak or cause contact injuries Any break in operations may have caused or coincided with a change (usually a drop) in pressure.

Some systems contain gases that are inherently toxic/flammable, some gases may be safe in normal process conditions but are now less safe due to changes in pressure or other conditions created by a recent shut-down. In any case, there is a legal duty to maintain pressurised systems (you can find out more from the HSE’s pages here) so it makes sense to check the system before re-starting operations, and to re-pressurise the system if required.

  • Areas used to store toxic and/or flammable gases that have not been entered for some time. This is likely to be a widespread danger because such areas are not always industrial. Swimming pool operators store chlorine; cafes, schools and colleges store gases for educational and catering purposes; food-makers, pubs and bars use gases in the manufacture and dispensing of beverages. If gas has leaked during a Covid-19 shut-down, it may endanger property and staff when operations begin again. Alternatively, the break could mean that gases are no longer stored at their optimum pressure or temperature.
  • It should also be noted that some stored goods may emit toxic or flammable gases if they have been left for a long period. For example, methane and hydrogen sulphide may be generated by organic matter that has begun to degrade or ferment.
  • Re-starting production or operations where materials/chemicals have been left unattended for some time can also be hazardous. For example, anything stored at a specific pressure may have experienced a change in that pressure, and materials stored in sub-optimal conditions (e.g. in terms of ambient temperature, pressure, exposure to light or operation) may now be unfit for purpose or even dangerous.

What should I do before re-starting operations?

Gas hazards should form part of your re-starting operations risk assessment.

When it comes to gas, Crowcon has a wealth of knowledge gathered over many years and from many installations. If you need reliable information about the gas-related dangers that may arise on your own return to operations, check out our ‘Talking Gas’ information hub, which is full of free resources to download, and our ‘Insights’ knowledge base. And if you have any other questions relating to the post-Covid return, please get in touch.

 

How aware of cross-sensitivities when using gas detectors are you?

In a perfect world, gas detector sensors would identify, isolate and measure specific gases and give precise readings for each gas in any context. Unfortunately, technology allows us to come close to that but not to achieve it completely. That is why, when dealing with electrochemical toxic sensors, we have the challenge of cross-sensitivities, sometimes known as ‘interfering gasses’.

Gas detectors generally detect a specified gas and give an alarm and/or reading in proportion to the level present. Cross-sensitivity occurs when a gas other than the gas being monitored/detected can affect the reading given by an electrochemical sensor. This causes the electrode within the sensor to react even if the target gas is not actually present, or it causes an otherwise inaccurate reading and/or alarm for that gas. Obviously, this puts the person using the sensor at risk.

Inaccuracies caused by cross-sensitivity

How not to use a gas detectorCross-sensitivity may cause several types of inaccurate reading in electrochemical gas detectors. These can be positive (indicating the presence of a gas even though it isn’t actually there, or indicating a level of that gas above its true value), negative (a reduced response to the target gas, suggesting that it is absent when it is actually present, or a reading that suggests there is a lower concentration of the target gas than there is), or the interfering gas can cause inhibition.

Inhibition occurs when the sensor simply fails to register the target gas when it is exposed to the target gas and the inhibitor together, or the inhibitor causes the sensor to stop registering the target gas for some time (which may be hours or even days) after exposure to the inhibitor.

Here are some examples of each error type:

  • Positive response error: a CO sensor has a positive response to H2 at a rate of 60%. Thus, when the sensor detecting CO sees 200ppm of H2 it indicates 60% of 200ppm (around 120ppm).
  • Negative response error: an SO2 sensor has a –120% response to NO2. So, if it sees 5ppm of NO2 at the same time as 5ppm of SO2, the reading is reduced by 6ppm, which (depending on the type of sensor involved) gives a 0ppm reading or negative value.
  • Inhibition: SO2 sensors may be inhibited by NH3, and take many hours to recover and respond to SO2

All of these errors can have adverse effects. Clearly, danger arises when toxic gas is present and the sensor does not read correctly. But even when cross-sensitivity causes an over-reading or false positive, time and resources can be wasted by needless evacuations, ventilation and other unscheduled downtime.

Some manufacturers publish cross-sensitivity data and charts, and these can give some indication of how cross-sensitivities may influence readings in those products. However, it is important not to rely on these too heavily: there can be huge differences between electrochemical sensors, manufacturers may change their sensor designs and specifications at short notice, and scientific understanding is constantly evolving. So, it is a good idea to maintain dialogue with the manufacturer’s technical support team, who will be aware of the latest information and best placed to advise on a particular sensor. It is also sensible to ensure that any staff involved in gas detection are aware of the nature of cross-sensitivity and interference, and alert to its likely effects.

Keeping your gas monitors clean during COVID-19

During this challenging time, keeping your gas monitor clean is more important than ever to ensure you’re keeping yourself, and others, safe.

Cleaning your monitor

The following procedure and precautions should be noted if you intend to clean your Crowcon gas monitor to protect against COVID-19 transmission.

Gas monitors contain sensors that may be affected by the chemicals in cleaning compounds. In general Crowcon recommends cleaning with mild soap and a soft cloth taking care not to introduce excessive amounts of liquid into the product/sensors.

Alcohol-based cleaning products may cause a temporary response on some electrochemical sensors; potentially leading to false-alarms. It is recommended monitors are switched-off before cleaning and not switched back on until the alcohol has fully evaporated.

Cleaning agents that contain chlorine and/or silicones must be avoided, especially on monitors that contain pellistor-type flammable gas sensors as these compounds will ‘poison’ the sensor leading to permanent loss of sensitivity to gas.

Where gas monitor cleaning regimes are introduced or increased Crowcon strongly recommends that sensors are bump tested with the target gas periodically to ensure that sensors remain operational. Pellistor-type sensors in portable monitors should be tested every day before use as prescribed in the European standard EN60079-29 Part 1.

It is extremely likely that any viral agent could get trapped within the pump or filters within an instrument. Maintenance procedures should continue to be performed as described in the Operation and Maintenance Manual for the product and in-line with operating company policy.

For more information on how to keep you or your business safe during the COVID19 pandemic, get in touch and we’d be more than happy to help.

What is the life expectancy of my sensors?

Given the critical nature of gas detectors, it is important to know they are working correctly at all times. Many factors can affect the performance of gas detection sensors, and all sensors will fail eventually, so users must be vigilant and prepared to change their sensors when required. But changing sensors too early, when they actually have plenty of life left, can be a waste of time and money.

A further issue arises with purchasing and storing spares. Replacement sensors have a finite shelf life, which begins from the moment they are made. As time passes, they can degrade even if kept in ideal conditions (i.e. in a contaminant-free, temperature and humidity controlled environment  so the period between purchase and first use should be brief.

So, what should users do to extend the life of their sensors without putting people at risk?

Factors affecting sensor life

The life and/or performance of gas detection sensors can be affected by various factors, including:

  • Temperature
  • Humidity
  • Interfering gases
  • Physical factors, e.g. excessive vibration or impact
  • Contamination of or damage to the sensor e.g. by incorrect cleaning products
  • Contamination of filters or sinters e.g. by dust, sand or pests (yes spiders!)
  • Exposure to poisoning/inhibiting compounds even when the sensor is not powered.

There are multiple sensing technologies available and the life expectancy of a sensor is commonly linked to the technology employed. Electrochemical sensors tend to have a shorter life expectancy as compared to Infrared (IR) or catalytic sensors. The type of gas being detected can also have an impact of the life expectancy,  the more ‘exotic’ gases (for example chlorine or ozone) tends to be shorter than that of sensors monitoring the more common gases (carbon monoxide, hydrogen sulphide for example).

Most sensors will also suffer general wear and tear, and the damage caused is not always easy to detect, so the first rule for keeping sensors safe and in good working order is to undertake regular maintenance. This should include scheduled bump testing (also known as a gas or functional test) and calibration; while exposure to substantial volumes of gas may harm some sensors, the small amounts used in bump testing and calibration are absolutely fine

It is not always easy to tell that a sensor has failed; some of the techniques suggested are unreliable and this is not an area in which to take risks. The only sure-fire way to know a sensor is working correctly is through application of the target gas(es) in bump testing/calibration.

Planning gas sensor replacement

It makes sense for users to extend the life of their sensors as far as possible; they cost time and money to replace, after all. The ability to forward-plan and predict sensor consumption also makes sensor purchasing more efficient and helps to reduce the time spare sensors are kept in storage.

To predict and plan sensor replacement, users must understand the factors that influence their sensors’ performance. These will be specific to their own setting, which is why users must also be able to draw upon knowledge and experience built up through regular testing and calibration of sensors in their particular environment and applications.

Good quality sensors will come with a warranty, but while this may indicate a general life expectancy there are too many variables and too much at stake for it to stand alone. There really is no substitute for user knowledge and regular maintenance: with these in place, gas detector sensors are far more likely to live long and prosper.

Helping you stay safe during the BBQ season

Who doesn’t love a summer BBQ? Come rain or shine we light up our BBQs with usually the only worries being whether it will rain, or the sausages are fully cooked through.

While these are important, (especially making sure the sausages are cooked!) many of us are completely unaware of the potential risks.

Carbon monoxide is a gas that has received its fair share of publicity with many of us installing detectors in our homes and businesses, but completely unaware carbon monoxide is associated with our BBQs.

If the weather is poor, we may decide to barbeque in the garage doorway or under a tent or canopy. Some of us may even bring our BBQs into the tent after use.  These can all be potentially fatal as the carbon monoxide collects in these confined areas.

Equally with a propane or butane gas canister, we store in our garages, sheds and even our homes unaware that there is a risk of a potentially deadly combination of an enclosed space, a gas leak and a spark from an electrical device.  All of which could cause an explosion.

All of that said, BBQs are here to stay and if we use them safely, are a great way to spend a summer afternoon.  So, here is a selection of facts and tips from our safety team at Crowcon which we hope will help you enjoy a safe and delicious summer ahead!

 

Quick facts and tips about BBQ charcoals:

  • Carbon monoxide is a colourless and odourless gas so just because we can’t smell or see it, doesn’t mean it’s not there
  • Carbon monoxide is a by-product of burning fossil fuels, which include charcoal and BBQ gas
  • Always use your BBQ in a well-ventilated open area as it can accumulate to toxic levels in enclosed spaces
  • Never bring a charcoal into a tent, even if it seems cold. Remember a smouldering BBQ will still give off carbon monoxide
  • Be aware and act quickly if someone experiences the symptoms of carbon monoxide poisoning which include headaches, dizziness, breathlessness, nausea, confusion, collapse and unconsciousness. These symptoms can be potentially fatal

 

Quick facts and tips about gas cannisters:

  • Gas barbecues tend to use propane, butane or LPG (which is a mixture of the two)
  • Gas BBQs have holes in the bottom to prevent a build-up of gas. This is because gas is heavier than air so will accumulate in low areas or fill a space from the bottom up
  • To avoid the accumulation of gas, cannisters should always be stored outside, upright, in a well-ventilated area, away from heat sources, and away from enclosed low spaces
  • If you store your BBQ in the garage, make sure you disconnect the gas cannister and keep this outside
  • When you are using your BBQ, keep the cannister to one side so it isn’t underneath and close to the heat source and position the BBQ in an open space
  • Always keep the cannister away from ignition sources when changing cannisters
  • Always make sure you turn off the gas at the BBQ as well as on the regulator on the cannister, after use

 

Identifying Leaks from Natural Gas pipelines at a Safe Distance

The use of natural gas, of which methane is the principle component, is increasing worldwide. It also has many industrial uses, such as the manufacture of chemicals like ammonia, methanol, butane, ethane, propane and acetic acid; it is also an ingredient in products as diverse as fertilizer, antifreeze, plastics, pharmaceuticals and fabrics.

Natural gas is transported in several ways: through pipelines in gaseous form; as liquefied natural gas (LNG) or compressed natural gas (CNG). LNG is the normal method for transporting the gas over very long distances, such as across oceans, while CNG is usually carried by tanker trucks over short distances. Pipelines are the preferred transport choice for long distances over land (and sometimes offshore), such as between Russia and central Europe. Local distribution companies also deliver natural gas to commercial and domestic users across utility networks within countries, regions and municipalities.

Regular maintenance of gas distribution systems is essential. Identifying and rectifying gas leaks is also an integral part of any maintenance programme, but it is notoriously difficult in many urban and industrial environments, as the gas pipes may be located underground, overhead, in ceilings, behind walls and bulkheads or in otherwise inaccessible locations such as locked buildings. Until recently, suspected leaks from these pipelines could lead to whole areas being cordoned off until the location of the leak was found.

Precisely because conventional gas detectors – such as those utilising catalytic combustion, flame ionisation or semiconductor technology – are not capable of remote gas detection and are therefore unable to detect gas leaks in hard to access pipelines, there has been a lot of recent research into ways of detecting methane gas remotely.

Remote Detection

Cutting edge technologies are now becoming available which allow the remote detection and identification of leaks with pinpoint accuracy. Hand-held units, for example, can now detect methane at distances of up to 100 metres, while aircraft-mounted systems can identify leaks half a kilometre away. These new technologies are transforming the way natural gas leaks are detected and dealt with.

Remote sensing is achieved using infrared laser absorption spectroscopy. Because methane absorbs a specific wavelength of infrared light, these instruments emit infrared lasers. The laser beam is directed to wherever the leak is suspected, such as a gas pipe or a ceiling. Because some of the light is absorbed by the methane, the light received back provides a measurement of absorption by the gas. A useful feature of these systems is the fact that the laser beam can penetrate transparent surfaces, such as glass or perspex, so it may be possible to test an enclosed space prior to entering it. The detectors measure the average methane gas density between the detector and target. Readings on the handheld units are given in ppm-m (a product of the concentration of methane cloud (ppm) and path length (m)). In this way, methane leaks can be quickly confirmed by pointing a laser beam towards the suspected leak or along a survey line, for example.

An important difference between the new technology and conventional methane detectors is that the new systems measure average methane concentration, rather than detecting methane at a single point – this gives a more accurate indication of the severity of the leak.

Applications for hand-held devices include:

  • Pipeline surveys
  • Gas plant
  • Industrial and commercial property surveys
  • Emergency call out
  • Landfill gas monitoring
  • Road surface survey

Municipal Distribution Networks

The benefits of remote technology for monitoring pipelines in urban settings are now being realised.

The ability of remote detection devices to monitor gas leaks from a distance makes them extremely useful tools in emergencies. Operators can stay away from potentially dangerous leak sources when checking the presence of gas in closed premises or confined spaces as the technology allows them to monitor the situation without actually gaining access. Not only is this process easier and quicker, but it is also safe. Moreover, it is not affected by other gases present in the atmosphere since the detectors are calibrated to only detect methane – therefore there is no danger of getting false signals, which is important in emergency situations.

The principle of remote detection is also applied when inspecting risers (the above-ground pipes carrying gas to the customers’ premises and normally running along the building outside walls). In this case, the operators point the device towards the pipe, following its route; they can do this from ground level, without having to use ladders or access the customers’ properties.

Hazardous Areas

In addition to detecting gas leaks from municipal distribution networks, explosion-proof, ATEX approved devices can be used in Zone 1 hazardous areas such as petrochemical plants, oil refineries, LNG terminals and vessels, as well as certain mining applications.

When inspecting an LNG/LPG underground tank, for example, an explosion-proof device would be required within 7.5 metres of the tank itself and one metre around the safety valve. Operators therefore need to be fully aware of these restrictions and equipped with the appropriate equipment type.

GPS Coordination

Some instruments now allow spot methane readings to be taken at various points around a site – such as an LNG terminal – automatically generating GPS tracking of the measurement readings and locations. This makes return trips for additional investigations far more efficient, while also providing a bona-fide record of confirmed inspection activity – often a prerequisite for regulatory compliance.

Aerial Detection

Moving beyond hand-held devices, there are also remote methane detectors which can be fitted to aircraft and which detect leaks from gas pipelines over hundreds of kilometres. These systems can detect methane levels at concentrations as small as 0.5ppm up to 500 metres away and include a real-time moving map display of gas concentrations as the survey is conducted.

The way these systems work is relatively simple. A remote detector is attached beneath the aircraft’s fuselage (usually a helicopter). As with the handheld device, the unit produces an infrared laser signal, which is deflected by any methane leakage within its path; higher methane levels result in more beam deflection. These systems also utilise GPS, so the pilot can follow a real-time moving map GPS route display of the pipeline, with a real-time display of aircraft path, gas leaks and concentration (in ppm) presented to the crew at all times. An audible alarm can be set for a desired gas concentration, allowing the pilot to approach for closer investigation.

Conclusion

The range of remote methane detection systems is increasing rapidly, with new technologies being developed all the time. All these devices, whether hand-held or fitted to aircraft, allow quick, safe and highly targeted identification of leaks – whether beneath the pavement, in a city or across hundreds of kilometres of Alaskan tundra. This not only helps prevent wasteful and costly emissions – it also ensures personnel working on or near the pipelines are not exposed to unnecessary danger.

Because the use of natural gas is increasing worldwide we foresee rapid technological advances in remote gas detection in applications as diverse as leak survey, transmission integrity, plant and facilities management, agriculture and waste management, as well as process engineering applications such as coke and steel production. Each of these areas have situations where access may be difficult, combined with the need to put personnel protection at the top of the agenda. Opportunities for remote methane detectors are therefore growing all the time.

 

Explosion hazards in inerted tanks and how to avoid them

Hydrogen sulphide (H2S) is known for being extremely toxic, as well as highly corrosive. In an inerted tank environment, it poses an additional and serious hazard combustion which, it is suspected, has been the cause of serious explosions in the past.

Hydrogen sulphide can be present in %vol levels in “sour” oil or gas. Fuel can also be turned ‘sour’ by the action of sulphate-reducing bacteria found in sea water, often present in cargo holds of tankers. It is therefore important to continue to monitor the level of H2S, as it can change, particularly at sea. This H2S can increase the likelihood of a fire if the situation is not properly managed.

Tanks are generally lined with iron (sometimes zinc-coated). Iron rusts, creating iron oxide (FeO). In an inerted headspace of a tank, iron oxide can react with H2S to form iron sulphide (FeS). Iron sulphide is a pyrophore; which means that it can spontaneously ignite in the presence of oxygen

Excluding the elements of fire

A tank full of oil or gas is an obvious fire hazard under the right circumstances. The three elements of fire are fuel, oxygen and an ignition source. Without these three things, a fire can’t start. Air is around 21% oxygen. Therefore, a common means to control the risk of a fire in a tank is to remove as much air as possible by flushing the air out of the tank with an inert gas, such as nitrogen or carbon dioxide. During tank unloading, care is taken that fuel is replaced with inert gas rather than air. This removes the oxygen and prevents fire starting.

By definition, there is not enough oxygen in an inerted environment for a fire to start. But at some point, air will have to be let into the tank – for maintenance staff to safety enter, for example. There is now the chance for the three elements of fire coming together. How is it to be controlled?

  • Oxygen has to be allowed in
  • There may be present FeS, which the oxygen will cause to spark
  • The element that can be controlled is fuel.

If all the fuel has been removed and the combination of air and FeS causes a spark, it can’t do any harm.

Monitoring the elements

From the above, it is obvious how important it is to keep track of all the elements that could cause a fire in these fuel tanks. Oxygen and fuel can be directly monitored using an appropriate gas detector, like Gas-Pro TK. Designed for these specialist environments, Gas-Pro TK automatically copes with measuring a tank full of gas (measured in %vol) and a tank nearly empty of gas (measured in %LEL). Gas-Pro TK can tell you when oxygen levels are low enough to be safe to load fuel or high enough for staff to safely enter the tank. Another important use for Gas-Pro TK is to monitor for H2S, to allow you judge the likely presence of the pryophore, iron sulphide.

Servicing for safety… A visit to the oil refinery

Working in the office makes it easy to focus on the individual tasks and get detached from how our products are making a difference to people’s lives. One of our customers was kind enough to facilitate an onsite visit so that Andrea (our Halma Future Leader on a marketing placement) could see first-hand how our products are used and who the end users are. This meant a visit to an oil refinery to see where our Crowcon portable gas detectors are used.


“The main thing that surprised me was the sheer size of the site. The oil refinery was very spaced out and it took us 10 minutes to walk from the entrance of the site to where the Crowcon engineer’s based. The engineers and employees around different parts of the refinery wore Hi Vis jackets, big safety boots, hard hats and all appeared to have personal gas detectors. During a quick site tour, I learned the products of the oil refinery are not limited to gas or petrol, but also tar, asphalt, lubricants, washing up liquid, paraffin wax and much more.

The products are all stored in big containers with pipes all over the site. Most of the products are highly flammable which explains the big focus on safety. In the distance, there were a few dome shaped containers which are pressurised vessels. If one of them were to explode, it would have a 10 mile blast radius. Suddenly I had the urge to leave and drive about 10 miles.

Crowcon’s engineer base was full of orange T4s, Gas-Pros as well as an army of “Daleks”, I mean Detectives, awaiting calibration and service. While the harshness of this industrial environment was evident from their appearance, they were otherwise in good working order, and the service engineer worked through the devices quickly.

The end users think of them as a simple device they have to wear to do their job, and they like the simplicity and reliability of Crowcon devices. The Detectives get thrown around and Gas-Pros are almost black is comparison to the usual orange, which just showcases how important the robustness of our devices is. The dangers of this working environment are not generally a big concern to the users, this is everyday life to them. Our devices help ensure they go home after a tough shift. Ensuring the devices are functioning properly is down to the service engineers, and they need to think for the users to ensure that the devices are being used properly.

Seeing Crowcon’s devices being used and the number of times someone enquired if the devices are calibrated and ready to go back into action, highlighted just how important use of portables as part of the safety regime  is considered. “Quality” and “robust” is how users describe Crowcon products and even though they may now treat them like the life saving devices they are, the devices are regularly used and valued. They make a very flammable and dangerous environment a safer place to be.”

Changes to Workplace Exposure Limits (WELs)

What Are Work Place Exposure Limits?

Workplace exposure limits (WELs) provide a legal maximum level for harmful substances in order to control working conditions.

Directive and National Standards

The EU Directive 2017/164 establishes new ‘indicative occupational exposure limit values’ (IOELVs) for a number of toxic substances. The UK Health & Safety Executive (HSE) has decided to change UK statutory limits to reflect the new IOELVs. This decision by the HSE has been taken to comply with Articles 2 and 7 of the Directive requiring Member States to establish the new occupational exposure limit values within national standards by August 21st 2018.

Gas Detector Alarm Thresholds

The exposure limits defined in this Directive 2017/164 are based on the risks of personal exposure: a workers’ exposure to toxic substances over time. The limits (configured into gas detectors as ‘TWA alarm levels’) are expressed over two time periods:

  • STEL (short-term exposure limit): a 15 minute limit
  • LTEL (long-term exposure limit): an 8-hour limit

Portable (personal) monitors are intended to be worn by the user near to their breathing zone so that the instrument can measure their exposure to gas. The instruments TWA (time-weighted) alarms will therefore alert the user when their exposure exceeds the limits set within the national standards.

Portable monitors can also be configured with ‘instantaneous’ alarms which activate immediately when the gas concentration exceeds the threshold. There are no standards to define alarm levels for instantaneous alarms, and so we have these generally set at the same thresholds as the TWA alarms. Some of the new TWA thresholds are low enough to make frequent false alarms a significant problem if they were also adopted for the instantaneous alarm setting. Therefore, new portable instruments will retain the current instantaneous alarm thresholds.

Fixed gas detectors only utilise ‘instantaneous’ alarms as they are not worn by the user and therefore cannot measure an individuals’ exposure to gas over time. Alarm levels for fixed detectors are often based on the TWA alarms as these are the only published guidelines. HSE document RR973 (Review of alarm setting for toxic gas and oxygen detectors) provides guidance on setting appropriate alarm levels for fixed detectors in consideration of site conditions and risk assessment. In some applications where there may be a background of gas it may be appropriate for fixed detector alarm levels to be set higher than those listed in EH40 to prevent repeated false alarms.

Re-configuration of Gas Detector Alarm Thresholds

Users of portable gas detectors who choose to adjust their instrument alarm thresholds to align with the Directive can easily do-so using a variety of accessories available from Crowcon. For full details of calibration and configuration accessories visit the product pages at www.crowcon.com.

Other documents you may find useful:

http://www.hse.gov.uk/pubns/priced/eh40.pdf

http://www.hse.gov.uk/research/rrhtm/rr973.html