Lone worker monitoring – Man down alarm – Advice and experience sought. - Page 1
Forum section: electronics / general

author: Mr.B
author_rank: Unknown
timestamp: June 07, 2017, 10:13:02 am
content: tl;dr;I am looking for a lone worker monitoring system that is effective, cost efficient and actually works.The long read…Our company is a cold chain logistics provider specialising in controlled environments for export products from New Zealand. We store, pack and export both frozen and chilled product.We have high risk environments in which our staff are expected to perform their duties. These environments include such areas as; low oxygen atmospheres, freezing temperatures, heights, condensation, slippery surfaces, etc.Our existing controls and precautions are now being considered insufficient under law and by our peer companies, auditors and health and safety consultants.We are looking for a solution to raising an alert to a third party that can attend to the emergency in a timely fashion.We have tried a number of potential systems and evaluated a number of others:1. We spent a fortune on a 433MHz based system that has ‘access points’ installed throughout the site with a cell phone sized device that is carried in the employees overalls pocket. If the device is lying down, rather than vertical in the pocket, for more than 60 seconds, the device alerts a monitoring company in Christchurch – some 350km away from the Nelson site.There was two major issues with this system:A) The response time from the monitoring company could be measured in hours and therefore the employee could easily be well and truly dead before anyone arrived.B) The employee working while leaning over a piece of equipment, or lying on their back doing some maintenance, would activate an alert when it wasn’t the case.This system cost more than NZD250k to install and was only used for three months… Total waste of money… (I was not a decision maker on this project.)2. We have tried the “two workers”, buddy system… Not the answer.Paying two wages for one job is not such a big deal, however the real risk is that both workers can be exposed to the same risk – perhaps low oxygen atmosphere.3. Suggested options have been devices such as the Samsung smart watch that has an SOS alert feature. It depends upon being connected to a working cell phone, which is fine because all employees have a company phone. However, time to response has been questioned with this type of solution.So… What experience do you have with this type of requirement?I would really appreciate your suggestions and advice.Many thanks…Edited to remove period at start of subject.

author: chris_leyson
author_rank: Super Contributor
timestamp: June 07, 2017, 11:20:19 am
content: Worked for a company a long time ago that designed a prototype lone worker transmitter, 433MHz based, that used mercury tilt switches. If there was no movement for some length of time it would send a message to a nearby receiver. We were trying to sell it to the UK fire service but they rejected it. These days tilt switches could be replaced by accelerometers but I think the smart watch or similar approach is probably a good solution because in most cases the 'lone worker' is doing a manual job and always moving their hands around.

author: MagicSmoker
author_rank: Super Contributor
timestamp: June 07, 2017, 12:25:48 pm
content: Assuming you have cellular service supporting a data connection - either from actual telecom providers or a local repeater - then there are a number of smartphone apps that can automatically send an email or text message in the event someone hasn't moved for a period of time. I imagine this sort of thing would work a lot better as a watch app, but, the phone versions appear to be cheap. See, for example,https://play.google.com/store/apps/details?id=and.dev.mandown.alert&hl=en(Not endorsing this app nor do I have any experience with it).

author: CJay
author_rank: Super Contributor
timestamp: June 07, 2017, 12:57:15 pm
content: All the Cellphone/smartwatch based systems rely on a smartphone having charge, being in service and being in range of the device so if a worker forgot to charge it or the insulation of the cold room blocks cell signal or the phone is left on a table outside the room, they're screwed, too many variables where someone's life is in potential danger.Speak to your insurance company, the authorities, trade organisations etc. etc. and see if they have a list of approved systems, you may well find they won't insure you if you don't have a system from their list.

author: technix
author_rank: Super Contributor
timestamp: June 07, 2017, 01:04:28 pm
content: For wider range wireless coverage you may be able to get Wi-Fi into the locations with a few strategically placed access points. Yes Wi-Fi access points inside the cold rooms. Then COTS smartwatches would work without a smartphone.

author: Gribo
author_rank: Frequent Contributor
timestamp: June 07, 2017, 02:15:35 pm
content: In my previous job, we built similar systems. The product could detect man falling from a standing position (Fainting), climbing stairs, running etc. It also used the 433MHz band. Depending on the number of cells and employees, 250K$ one time cost might not be expensive. Consider a cellular high-reliability costs per employee, and you cover it within a year or two. As for the response time issue, the only solution is a local response team.

author: vodka
author_rank: Frequent Contributor
timestamp: June 07, 2017, 04:26:34 pm
content: Quote from: Mr.B on June 07, 2017, 10:13:02 amBesides add other trouble, when the device is out the pocket and the worker could forget to pick it." the device alerts a monitoring company in Christchurch – some 350km away from the Nelson site". Is that a joke? So , whom do they call , Emergency or the boss or supervisor of plant?QuoteAn low-oxygen or toxic air alarm, autonomous team with mask(for ammonia leaks) and radio or walkie-talkies plus a companion.https://youtu.be/QHNg1BDgmAYI think that is more cheapest than the first optionQuoteYou keep in the mind that the worker on case accident could suffer a traumatic amputation or be burnt, and the smartwatch could be destroyed

author: nctnico
author_rank: Super Contributor
timestamp: June 07, 2017, 04:33:39 pm
content: Quote from: vodka on June 07, 2017, 04:26:34 pmI'd expect the device to at least keep in touch which the control room through regular 'I'm still working' messages.

author: james_s
author_rank: Super Contributor
timestamp: June 07, 2017, 05:02:57 pm
content: I suppose you could have an alertness monitor like they use in trains where it beeps at various intervals and the operator has to respond by pressing a button otherwise action is taken. It's a bit of a hassle for the workers but it may be less of a hassle than false alarms.

author: Mattylad
author_rank: Regular Contributor
timestamp: June 07, 2017, 06:11:20 pm
content: I'd also have 2 way radios in use so that if there is an alert they can be contacted to confirm false alarms before sending out the coastguard, fire department and the tea lady.

author: Mr.B
author_rank: Unknown
timestamp: June 08, 2017, 04:17:02 am
content: Thanks all for your input.@MagicSmoker: I will investigate the range of cell phone apps available and see if anything will fit the bill.@CJay: Unfortunately the insurance companies will not recommend anything through fear of liability. They refuse to make recommendations on anything related to health and safety.ACC (Accident Compensation Commission) who administer health and safety in New Zealand will not make recommendations for the same reason.@technix: We have full WiFi coverage inside the rooms. This is a requirement to connect our freezer grade forklift mount computers. I will investigate your suggestion further.@vodka: “An low-oxygen or toxic air alarm…”Everyone carries a Gas Badge, manufactured by Industrial Scientific. These alert on low oxygen levels.@james_s: I quite like that idea. I will need to investigate how we might implement such a system and run it past the health and safety committee.@Mattylad: Unfortunately radios are not practical. The most likely scenario for lone workers is where someone is called in after hours for a breakdown or suchlike. Other workers are not necessarily on site at the time.Again, thank you all.I will keep searching.

author: Lightages
author_rank: Unknown
timestamp: June 08, 2017, 04:46:58 am
content: 2 person or 3 person working systems are the only way IMHO. With the proper training, and proper safety equipment, there should be low probability of accidents. If the conditions are so dangerous that someone can die and become injured then there should never be one worker. A battery operated alert system will not save anyone. To consider allowing a person to work alone in an environment where it is known to be hazardous is criminal IMHO.There are already protocols in force in many countries to prevent worker injuries in cases like this. They should be followed instead of asking random people on the internet how to prevent injuries and deaths.

author: Rick Law
author_rank: Super Contributor
timestamp: June 08, 2017, 05:04:42 am
content: Quote from: Mr.B on June 07, 2017, 10:13:02 amI think what you wrote dictated a solution already. In your words, "The response time from the monitoring company could be measured in hours and therefore the employee could easily be well and truly dead before anyone arrived." So, unless you canchange the response time of emergency help, the monitoring and the alert equipment are irrelevant.Therefore, you either have to find ways to make the buddy system work (have one in an isolated area not sharing the dangerous environment), or put help near by before you worry about the alert/monitoring systems, or both.Otherwise, having a perfect monitoring/alert system will just let you know that your guy is dying and there is nothing you can do about it.

author: CopperCone
author_rank: Super Contributor
timestamp: June 08, 2017, 05:12:07 am
content: Quote from: chris_leyson on June 07, 2017, 11:20:19 amIt was probably seen as redundant (as firefighter SCBA have little ball bearings in them.. if you watch fire fighters standing around in gear they will wobble once in a while or shake their hips). If it was integrated into the pack it could work. A good feature would be to link it to the entry badge that firefighters tend to carry (usually department policy is to hang up your fire entry badge on a cone outside of the structure when you are going in, so it is known that you are doing interior work (and you retrieve it right after going out of the structure).

author: tautech
author_rank: Super Contributor
timestamp: June 08, 2017, 05:47:47 am
content: Mr B, could the health monitoring gadgets we see on our rugby players be adapted for your needs ?Maybe the monitoring SW can be modified to include the parameters you require.http://statsports.com/

author: Mr.B
author_rank: Unknown
timestamp: June 08, 2017, 06:00:45 am
content: Worth investigating @tautech, however I think @RickLaw has hit the nail on the head…It is the time to response that may render any wearable/carryable device redundant, and therefore the system comes back to multiple employees in attendance.I will submit my ideas to the H&S committee and leave it with them.Thank you all.

author: aargee
author_rank: Frequent Contributor
timestamp: June 08, 2017, 07:08:53 am
content: What's been said.Multiple workers as a team is the only option in long response time situations, everything else is only a pre-warning for legal teams.

author: Someone
author_rank: Super Contributor
timestamp: June 08, 2017, 08:08:44 am
content: Quote from: Rick Law on June 08, 2017, 05:04:42 amIt often comes down to awareness of the other people on site, the typical lone working radios will notify all other people on site that there is a problem:http://www.vertexstandard.com/anz/loneworker/Then its a matter of having them respond quickly and appropriately (especially for the oxygen depletion hazards), a central control officer who can co-ordinate where people are working at all times and direct the response can be critical in a large and complex site with few people on it. The OP might be able to find a solution with their current provider and better co-ordination on site.You can't do lone work safely on a site alone, it needs well trained and informed people nearby for the fast response.

author: Halcyon
author_rank: Unknown
timestamp: June 08, 2017, 08:26:58 am
content: The only experience I've had with these sorts of alarms are the ADSUs (Automatic Distress Signal Unit) worn by firefighters. It's essentially a device worn by the firefighter and is "armed" (by removing a pin) before they enter a building or fireground. If movement isn't detected for 5-10 seconds, it goes in to "warn" mode which allows the wearer to shake the unit to go back into standby. If after 7 or so seconds in warning mode without further movement, it goes into a full alarm which is loud enough to be heard by those outside (even over all the background noise). The only way to shut it off is for the firefighter to walk out themselves and retrieve the key to disarm it, or they get dragged out by their colleagues.This was about 10-15 years ago. I'm sure technology has improved that it sends a wireless signal back to the truck and/or base. The added advantages of these units are that they are very robust (designed to withstand radiant heat from fire) and are intrinsically safe.Wormaldmake a few models as doesDräger.

author: CJay
author_rank: Super Contributor
timestamp: June 08, 2017, 09:20:02 am
content: Quote from: Mr.B on June 08, 2017, 06:00:45 amI think Rick Law hit the nail on the head too, I've since spoken to a colleague who works on site at a cheese factory where maintenance have equipment and alarms manufactured by the same people (Tyco) who make breathing apparatus for firefighters (dread to think what cheese they make that needs BA but I want some*).However, they have strict protocols for hazardous area work, they never work alone and have a check out/check in system where site security should always know they've entered a hazardous environment and have colleagues on site who are trained for emergency situations.Hope you get the result your guys need* They've got a factory shop!! Yes, I know, it's for maintenance work in areas where there may be higher concentrations of inert gas or hazardous gases (ammonia) to prevent bacterial bloom or sterilise surfaces which come into contact with foodstuffs but the story of the exploding cheese is rather impressive.

author: VK5RC
author_rank: Unknown
timestamp: June 08, 2017, 10:34:23 am
content: +1 re observer-colleague in known hazardous environment.I would add colleague would need some training in safe evacuation/ retrieval - otherwise 2 then in trouble.

author: Halcyon
author_rank: Unknown
timestamp: June 08, 2017, 11:02:49 am
content: Quote from: VK5RC on June 08, 2017, 10:34:23 amYou make a good point. If it'sknownto be hazardous (especially at short/no notice) then common sense would dictate no man goes in alone or at least not without adequate PPE. Technology can fail, so assume all communication to the outside world is dead.If the only hazard is a non-life supporting atmosphere, then supplemental breathing devices (commonly called EEBD - Emergency escape breathing device) should be a strong consideration on top of any communications, that way, a person or persons have a chance to save themselves.To do any less is likely to be deemed negligent.

author: TerraHertz
author_rank: Super Contributor
timestamp: June 08, 2017, 11:36:27 am
content: When I was working on ship refurbishments at Garden Island, for confined spaces working we used a strict buddy system. One person stayed outside the confined space (and had a radio), while one person worked inside. And was never to be out of sight of his observer. This was for potential bad air, and also electrocution hazards.For those who don't know, very low oxygen levels can make a person lose consciousness very suddenly and without much perception of there being a problem. The body has no blood-oxygen level sensing, only high CO2, which makes you pant. If the air suddenly has very low or zero oxygen, you actually _lose_ blood oxygen rapidly since it diffuses out of your blood to the air in your lungs. You will pass out much faster than you would if you just held your breath. Like in less than 15 seconds.I've actually experienced this, in a near-zero oxygen atmosphere, and it's very scary. Was Urbexing, in mine-related structures. I got myself out, reaching good air just as I was finally losing all function. Took maybe 4 seconds from realizing I was losing vision, to collapsing semi-conscious outside the space. I'd climbed up a ladder to get out, while having zero vision and losing sensation in hands and feet. In 4 seconds. I was alone there so if I hadn't immediately recognized what was happening, and had hesitated, I'd be dead.In such cases, 'response time' had better be less than 1 minute, or you have a body to retrieve.People not knowing the risks and symptoms of oxygen starvation, has resulted in many instances of a series of people going into a space to rescue others who passed out, and themselves passing out and dying.

author: VK5RC
author_rank: Unknown
timestamp: June 08, 2017, 11:40:09 am
content: Wasn't this the original Murphy's law - that some things that can foreseeably go wrong and should be prevented or accounted for?( I think he was a NASA engineer - but not called Murphy )

author: grumpydoc
author_rank: Super Contributor
timestamp: June 08, 2017, 11:52:12 am
content: This video with Jeremy Clarkson illustrates the danger of low O2Towards the end he can't even concentrate enough to put his own oxygen mask back on.

author: Mr.B
author_rank: Unknown
timestamp: June 08, 2017, 08:37:32 pm
content: The atmosphere hazards exists in three areas:1.Rooms full of fruit such as apples, pears and kiwifruit (not in the same room of course).The fruit causes elevated levels of carbon dioxide.The digital readout of the CO2 level is on a display outside the room door.We have protocols in place, that meet the Worksafe New Zealand standards, for how long a person is allowed in the room by what the CO2 % is.Everyone also carries clip on gas detectors, marketing name is Gas Badge.2.Rooms full of apples where the atmosphere is deliberately 100% Nitrogen.This is to keep the fruit longer.Our friends from the Netherlands will know all about this. IIRC they invented the process for keeping tulips longer.These rooms are sealed and locked. Nobody is allowed in.3.The plant and atmosphere generation service areas to supply the requirements of item 2 above.This consists of two corridors 10m wide and 100m long, above the storage rooms.The corridors contain the atmosphere feed and return pipes and large plastic bags called lungs, that hold Nitrogen in preparation for purging into the rooms.There is an open vent at the northern end of each corridor and a fan that runs 24/7 in a vent at the southern end.Continuous slow air exchange is maintained to avoid buildup of any leaked gasses.The photo below gives half an idea of the working environment, showing the last 30m to the door. The lungs and BA sets are out of picture to the left.I am unable to get a more recent photo just at the moment as we are in the middle of the apple season here and 'I want to take a photo' is not a good enough reason to go up there.Quote from: Halcyon on June 08, 2017, 11:02:49 amEach corridor has 11 such devices spaced at 10m intervals.My personal opinion is that measures are sufficient if the company adopts a two worker policy.However, my opinion does not count... It is up to the H&S committee.

author: TerraHertz
author_rank: Super Contributor
timestamp: June 10, 2017, 03:19:14 am
content: Quote from: grumpydoc on June 08, 2017, 11:52:12 amActually that was demonstrating high altitude effects, dropping air pressure while maintaining normal atmosphere gas ratios. At low pressure the body can't keep blood O2 saturation levels high enough. And they only took him a little way into the 'death zone.'Something interesting we (Urbex group) found while doing group explores of underground spaces while carrying gas safety monitoring instruments, is that different people have quite different susceptibility to low O2. One time, while everyone else was coping OK (iirc the O2 level was about 16%) one of the group began vomiting, semi-coherent and nearly unable to walk. Time to leave.

author: Lightages
author_rank: Unknown
timestamp: June 10, 2017, 05:45:46 am
content: I have already stated my opinion, but I must again. This subject is very sensitive to me. I was a health and safety representative for a union at a steel production company for 7 years. This stuff is not a joke and it cannot be considered discounted in any way. Any condition where a worker is exposed to hazardous conditions and is alone is criminal, period. There should NEVER be a situation where this should happen. There is no electronic solution to safety. You need two workers at least with one outside of the danger to monitor and call for help should a problem arise. There are many procedures to help ensure the safety of a worker. This is not rocket science and any company looking to replace proper safety procedures with an electronic device should be shut down, period. Nobody should need to be put into risk for the profit of a company. NEVER!Two or three workers, plus proper emergency procedures to securely rescue anyone who is in danger is the first concern. Any other concern is money grabbing assholes trying to make money on the risk of someone's life.Anyone giving suggestions here to help a company avoid their proper responsibilities should just shut up and stop giving vapid advice. It is dangerous and irresponsible. There are regulations and procedures for this.People might think I am going over the top, but I have many stories. One for an example:In the steel production plant where I worked, steel roils are flattened. The edges of these rolls of steel get wavy. To trim the edges there are rotary sheers that trim the edges and send the strips of irregular steel to a rotating spool to collect the trimmings. The trimmings vary in thickness and sometimes break. So the operator of the trimmer needs to go to the baler and re-connect the steel to the spool. This cannot be done while running as it is very dangerous to do so. Because of this, there is a dead man switch at the controls to prevent the operator trying to connect the strip while the machine is running. Well the operators learned to put a piece of steel on the switch to keep the trimmer running to make it easier to put the trimmed strip back on the baler.The solution was to put another switch on the operators seat. They learned to put another weight on the seat.The next solution was to put another foot switch. They put another weight on that switch.One day a person died. A worker found the trimmer running and the operator nowhere in sight. There were three weights on all the dead man switches. He went to the baler room to look for the operator. I spoke to him afterward. This is his story to me, paraphrased."I went down to the baler and I saw that it was running. There was a really bad smell I had never smelled before. As I entered, I saw a stain of blood on the floor and a streak of blood from that stain. I followed the streak to the ball of steel winding on the spool. There was a bunch of guts and meat and bones sticking out of the spool of steel. I started to realize what had happened and started to feel sick. I followed the streak of blood back to the stain and then saw that near the stain was the head of my friend which had been popped off as the steel wound around the spool. I immediately went outside and started throwing up. As I was doubling over and throwing up, my boss arrived and asked me what was wrong. I tried to explain and tell him to not go in, but he did. He immediately came back out and starting vomiting beside me."He was given 2 months of sick leave with counseling.What is the point of this story? Nothing will stop the carelessness, or impatience, or complacence of a worker. There needs to be another person watching, or two, so that a worker will not take shortcuts or try to take that one chance. Devices do nothing. I have many other similar stories and a device can never stop a person from trying to please the boss, or prove their worth, or speed up their getting back to sleeping in their chair. Devices will never put on a Scott Air Pack and go in to rescue an idiot who wandered into an area with no oxygen. Anytime profit or personal reputation or pride are involved, idiots will kill themselves or companies will let them do so. This cannot be on the back of a simple device or devices.I don't write this to impose my ego on anyone but rather for my concern for other humans and what I know and is more than evident. Stop this line of inquiry, it leads to nothing good.

author: ed_reardon
author_rank: Regular Contributor
timestamp: June 10, 2017, 06:45:55 am
content: Another 'hazard areas' workers here.What I have seen (and sorry I've no idea if it's available in NZ) from a company I work along-side is essentially an ID badge (it functions as an ID badge) worn on a lanyard around the operators neck, it combines as a help pager and 'man down' system. Being worn as an ID badge it removes a lot of erroneous alarms as generally an ID badge worn around the neck is a difficult thing to hold horizontally for any period though daily activity.It acts as a two-way coms device and the mic channel on the badge can be opened remotely by the control centre, as well as a panic button on the 'badge'. I believe the system can be set up so that it's either monitored directly by the company OR it can be managed by the supplier call-centre.Me, personally, I work in a two-man team where confined space entry is required, but the 'top man' is working at atmosphere outdoors so the top-man shouldn't be overcome by anything untoward; then a conventional set of gas-monitors, escape BA for the operative 'in the hole' as well as a tripod rescue system constantly connected to the operator at risk.

author: grumpydoc
author_rank: Super Contributor
timestamp: June 10, 2017, 07:48:53 am
content: Quote from: TerraHertz on June 10, 2017, 03:19:14 amAgreed, but it doesn't matter why the partial pressure of oxygen is low, the effect on your brain is much the same.

author: German_EE
author_rank: Super Contributor
timestamp: June 10, 2017, 08:15:26 am
content: Add one more vote for the buddy system, if it wasn't for that I would be dead or crippled. As for morons who disable safety interlocks, they deserve to be fired on the spot.Any electronic devices should be an ADDITION to the above, not a substitute.

author: tooki
author_rank: Super Contributor
timestamp: June 10, 2017, 10:00:28 am
content: Quote from: Lightages on June 10, 2017, 05:45:46 amThanks for sharing.So lemme ask, what was the motivation for for workers to defeat every safety interlock that was put in place? It seems to me that the root cause of the problem was an incentive to not pause production for any reason.

author: Lord of nothing
author_rank: Super Contributor
timestamp: June 10, 2017, 10:22:41 am
content: Sorry i cant read every word in this tread...I have some idas:a) Take an Business Smartphone for example from Zebra, Honeywell, Panasonic (?),... the have some special App for Monitoring.b) Take an Radio System. You might have have for a Freq. Licence.Some Brands have Solution for like Motorola, Hytera, Kennwood,... (TYT but with there Radio is just a Self service)c) You also could take the ascom i62 its the only Wifi Radio who I found.Please note you need some licence or buy the "highest" Version for all Features!And your Wifi Hotspot must suport the power saving features who are defined in a IEEE Standart if not the radio get very fast flat.

author: Lightages
author_rank: Unknown
timestamp: June 10, 2017, 08:28:01 pm
content: Quote from: tooki on June 10, 2017, 10:00:28 amThe motivations are always one of the following, laziness, frustration with a procedure not working, bad education in the dangers, pressure to keep production running, fear of being fired, and the worst is "I am too smart to need to follow the rules". In the case of this incident, probably laziness and "I am too smart to need to follow the rules". As I said, this is just one of many examples of why people need to watch people, not some dumb thing that can be bypassed, ignored, or can fail.

author: TerraHertz
author_rank: Super Contributor
timestamp: June 11, 2017, 05:45:04 am
content: Quote from: grumpydoc on June 10, 2017, 07:48:53 amI wasn't disputing that, only making the point that they took him just a little way into 'too low'.A more memorable video would be of someone suddenly breathing room-pressure air at less than 10% oxygen. They wouldn't notice anything at all, except after a few seconds they'd be unconscious. A few seconds more and they'd be dead.Incidentally, this is also how people taking refuge in swimming pools from a bushfire, can end up drowned. Fire may use up most of the oxygen in ground level air, person in pool suddenly passes out, sinks and drowns.

author: MK14
author_rank: Super Contributor
timestamp: June 11, 2017, 05:57:21 am
content: Quote from: TerraHertz on June 11, 2017, 05:45:04 amBut could it also be too much carbon dioxide, which is heavier than air, so could collect in the pool.Worse still Carbon Monoxide, which (even in low concentrations, I believe) is well known to gradually make people unconscious and worse.Maybe that is why the following advises against it:http://www.latrobe.edu.au/education/downloads/bushfire_safety.pdfQuoteI guess they could be referring to carbon monoxide, carbon dioxide, other hazardous gases, or a lack of Oxygen. It is not clear to me which.