Open welding at nearby construction site

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lightblue
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Open welding at nearby construction site

Post by lightblue » Sun, 12 Jun 2011 1:18 pm

Hi all,

I'm faced with an unusual situation and not sure how to react.

Recently, the empty plot of land just outside my unit turned into a construction site for a new condo. I observed over the weekend that the workers have started welding work that is plainly visible from the windows facing the construction.

Really appreciate if anyone can provide some feedback/advice on the following questions running through my mind:

1. Is it safe to carry out welding in the open like this where anyone passing by or looking out from their windows can see it?I've got a toddler staying full time at home who loves to watch out from the windows.

2. Is there a distance beyond which the light from the open welding cannot pose a danger for the eyes?

3. Should I be really concerned and feedback to the relevant authorities?

4. What organization should I feedback to?

Thanks a ton.

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ksl
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Post by ksl » Sun, 12 Jun 2011 2:39 pm

I have had the problem with welding and eyesight, not sure of the safety distance, you should ensure your child is not able to look that way, to be on the safe side. You will notice the child rubbing eye's if effected.

It actually feels like sand in the eyes and is quite irritating.
You may find more information on searching the internet. Though i doubt Singapore is up to date on safety.
http://www.cpsc.gov/cpscpub/pubs/5109.html


NEA Singapore if you need to contact

http://app2.nea.gov.sg/index.aspx

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Post by x9200 » Mon, 13 Jun 2011 8:38 am

Welding typically generate light with higher amount of UV radiation but the actual hazard will depend not only on the distance but also on the source (type, power).
As KSL said, contact NEA when in doubts.

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Post by taxico » Fri, 17 Jun 2011 10:12 pm

there're many different types of welding equipment. some are more hazardous to eyeballs than others!

a quick look would unlikely harm your child and the farther away you are from the light source, the less intense the effect.

obviously if your child stares at any bright light for an extended period of time, it's not a good thing (light bulbs, the sun, the tv, etc).

if you're very concerned, the appropriate place to make a report would be MOM or the safety council(s).

but the easiest method is to educate your child about why he/she should not stare at it.

for now, i wouldn't worry too much about it if your child does not exhibit any physical signs of discomfort.

this fascination with bright sparks is common in children and he/she will soon be bored with the welding.

taxico, M.D.
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Post by beppi » Sun, 19 Jun 2011 12:01 am

Sheesh, some people have nothing else to do but worrying about nonsense!
Due to the simple laws of radiation propagation (Yes, I am physicist!), a doubling of distance from the source reduces intensity to 1/8 (that is 12.5% - TO 12.5%, not BY). The welding radiation is harmful for the eye at 1 or 2 meters distance, but you are probably 10 or more meters away - thus less than 0.003% of the harmful dose reaches your eye.
You are more justified closing your eyes every time the sun shines - natural light has way more harmful components!

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Post by Calmday » Sun, 19 Jun 2011 11:34 am

lightblue I have spent a lot of my adult life in fab shops and ship yards and think you asked a great question.
Like professor rude said, distance matters. I would still teach my child to not look at welding. If you ever get an eye burn you will know it but most of the time it won’t hit you until hours later (I know firsthand). Like KSL said, it feels like your eyes are full of sand. Extremely painful.

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Post by x9200 » Sun, 19 Jun 2011 12:37 pm

beppi wrote:Sheesh, some people have nothing else to do but worrying about nonsense!
Due to the simple laws of radiation propagation (Yes, I am physicist!), a doubling of distance from the source reduces intensity to 1/8 (that is 12.5% - TO 12.5%, not BY). The welding radiation is harmful for the eye at 1 or 2 meters distance, but you are probably 10 or more meters away - thus less than 0.003% of the harmful dose reaches your eye.
You are more justified closing your eyes every time the sun shines - natural light has way more harmful components!
I am not a physicist but assuming a point-source of the radiation, not knowing anything about the source, distance, number of welding spots and the duration of the process and then coming up with the No of 0.003% sounds like a nonsense to me :) Relax man, this is not a stupid question. People are using shields to separate such welding sites from the surrounding areas (more than 10m of exposure) and it is justified for a number of reasons including the basic fact that people may stare at it for longer time. I can ask you this basic question: if this is so safe would you have any objection your kid is staring at it every day for 30 min from a distance of 10m?

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Post by ksl » Mon, 20 Jun 2011 3:58 am

Yes, I am physicist,
So much for a physicits advice! I'm a welder and I recall many other variables being involved like exposure time too, my eye burn was well over 10 meters and i was probably exposed for 20 minutes, not looking directly but getting caught out a few times while working in the vicinity, by the time i had complained about the gear being used, I was effected for several days, and I've always known of the dangers. It is a safety issue that is rarely enforced on construction sites, and it should be enforced.

Quote:http://www.esabna.com/us/en/twi/minimum ... stance.cfm

What is the minimum safe distance from the welding arc above which there is no risk of eye damage? There is no clearly defined limit since the distance depends upon the exposure time, welding process, welding current and other environmental conditions. The US Army have carried out trials which propose distances of between 3 and 20 metres for an exposure time of 10 minutes for MMA (SMAW), MAG (GMAW) and FCAW in order for UV exposure to be below the US daily threshold limit value.

Other sources, however, state that all radiation from a welding arc is potentially hazardous and there is therefore no safe limit. At present the best advice is to screen off the area in which welding is taking place in order to protect completely workers or members of the public not equipped with adequate eye protection from the effects of the welding arc.

This link covers more safety issues besides welding! Many people are unaware of many many dangers in the home, and one of my favourites, is silly housewives who throw water onto a frying pan, while their is fat in it!

Young women and men really ought to learn the dangers in the home!
http://www.oxarc.com/welding_safety_guide.ydev

I was lucky last week when my 11 year old daughter was frying an egg, I was busy and not watching what she was doing....she wasn't aware of the dangers when fat gets too hot, that it starts to smoke and her reactions were very slow to turn the gas off. I had to dive in switch it off and take the pan away before it burst into flames, though the smoke alarm did go off, these are very silly events of a child trying to do good and ending up bad. So she learned her lesson and i had to give her another twenty minutes explaining why she should never touch anything without telling me first, so i can be there. I then explained the dangers of cooking and never to throw water onto a fat fire, has it makes it worse and spits the fire out of control.

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Post by curiousgeorge » Mon, 20 Jun 2011 7:28 am

beppi wrote:Sheesh, some people have nothing else to do but worrying about nonsense!
Due to the simple laws of radiation propagation (Yes, I am physicist!), a doubling of distance from the source reduces intensity to 1/8 (that is 12.5% - TO 12.5%, not BY). The welding radiation is harmful for the eye at 1 or 2 meters distance, but you are probably 10 or more meters away - thus less than 0.003% of the harmful dose reaches your eye.
You are more justified closing your eyes every time the sun shines - natural light has way more harmful components!
I am no a physicist, but I do question your theory.

The danger from welding - Photokeratitis (arc eye/snow blindness) - is a result of overexposure to UV. I don't know if UV is subject to the laws of radiation propagation, but it is certainly subject to Newton's Inverse Square Law which states that the strength of the UV is inversely proportional to the square of the distance from the source of the UV.

So a doubling of distance reduces the intensity to 1/4th, not 1/8th.

If the harmful distance is 2m, then from 10m away (5 X distance) you are subject to 1/25th (or 4%) of the harmful effects of welding...as anyones who has had arc eye will tell you, this is more than enough to produce pain.

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Re: Open welding at nearby construction site

Post by curiousgeorge » Mon, 20 Jun 2011 8:29 am

lightblue wrote:Hi all,

I'm faced with an unusual situation and not sure how to react.

Recently, the empty plot of land just outside my unit turned into a construction site for a new condo. I observed over the weekend that the workers have started welding work that is plainly visible from the windows facing the construction.

Really appreciate if anyone can provide some feedback/advice on the following questions running through my mind:

1. Is it safe to carry out welding in the open like this where anyone passing by or looking out from their windows can see it?I've got a toddler staying full time at home who loves to watch out from the windows.

2. Is there a distance beyond which the light from the open welding cannot pose a danger for the eyes?

3. Should I be really concerned and feedback to the relevant authorities?

4. What organization should I feedback to?

Thanks a ton.
1) No. Best practice is to shield with welding curtains, but they don't seem very popular on construction sites in SG

2) Yes. Assuming the most harmful kind of welding (Gas Metal Arc Welding with 95% Argon and 5% Oxygen mix, with a current of 350amps, you would need the following distances for the following exposure times to remain within the U.S. Daily Threshold Limit:

1 min / 6.7 metres
10 min / 21m
8 hours / 150m

But that kind of welding is mostly (not exclusively) stainless steel. Construction site welding is more often mild steel with CO2 gas at lower amperage or probably Stick welding so you could remain within the 8 hour threshold limit from a distance of approx 70m. (10m/10min).

Info here

3) Yes if it bothers you.

4) Many choices.
Start with the Main Contractor - details must be posted at entrance to the site. Don't bother approaching the site as even if you do get to talk to a foreman he will forget your complaint instantly. The Main Con will have some sort of community relations person.

You could try the Building & Construction Authority, who may have welding guidelines for members, and they may be willing to remind the Main Con.

For most nuisance construction issues, talk to the National Environment Agency Pollution Control Dept, they have an enforcement department. Use words like "unsafe radiation" to get their attention, as they might not recognise welding light as a pollution hazard.

If you want to go in armed, get a copy of Singapore Standard 510 for Welding and Cutting...I can't lay my hands on it now, but I would guess it has provisions for protecting people in the vicinity.

Failing all that, call the Workplace Safety and Health Council, tell them the problem and ask to see the site Risk Assessment for Welding...no company wants extra attention from the WSH ;)

Or...get really sneaky...

...make a complaint to NEA about stagnant water on the site, get them down to inspect the site every day...once the Main Con gets peeved with the interuptions, tell the Main Con the mosquito complaints will stop if the welders use curtains.

...or go to your doc "with" Arc Eye symptoms, he will wash it with cocaine solution (so no lasting effects!) then make a report to all of the above authorities that you have suffered an injury from their construction site...that will panic them into action!


HTH.

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Post by sundaymorningstaple » Mon, 20 Jun 2011 9:04 am

Sounds like some of the stuff we used to do out in the GOM back in the days before OSHA took effect. Hell, we even used shields when using Broco Rods for cutting underwater even when vis was virtually nil. Your eyes are precious. Take care of them. A modicum of commonsense will go a long way.

I've had sandy eyes syndrome more times than I care to remember due to the lack of shields on rig construction sites back in the 70's. Sometimes it was virtually impossible to get around in a busy yard without having flashes due to the lack of shields. Fortunately lots of the equivalent of EyeMo and a penchant for wearing sunglasses all the time back then caused no lasting damage.
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