Archive for the ‘Safety’ Category

What goes out must come in

December 5, 2010

On my Linked In page, I passed on a link to an article titled, “Makeup Air for Range Hoods” (http://www.greenbuildingadvisor.com/blogs/dept/musings/makeup-air-range-hoods).  The author, Martin Holladay, digs into the details of adding a larger range hood to a home.  In particular, he investigated whether consumers were warned about what could be the impact of adding such a hood to a home.  Mr. Holladay’s blog is a fair warning to consumers that they might not be warned about products that could have a negative impact on your home’s environment, and that impact could be hazardous.

In this post, as I promised on my LI page, I am going to dig into more detail about the impact the fan or other devices that change home pressurization could have on the home and potentially its occupants.  Let me start the same way.  Consider your home–or any building for that matter–as a box.  When air is removed from that box, replacement air has to come into the box to replace the air that is removed.  This replacement air is normally called makeup air by building professionals.  The issue is from where that makeup air comes.

If the home is air leaky, makeup air will come through openings in the building’s exterior shell, i.e. walls, roof, windows, doors, etc.  Leaks are usually a major issue because the air can come from many places.  Rehabbing older homes cuts down on the leaks, but usually cannot totally eliminate them.  But, even newer, so-called tight, buildings have air leaks.  The problem with air leaks in all buildings is mainly a thermal comfort issue because leaks cause drafts, and few people enjoy the feeling of a cold air stream inside the home on a cold day.  Another just as important issue is that if air can come in through a leak, it can go out through a leak, which translates into loss of heated or cooled air.  But, air streams flowing past hoods, fireplaces, ventless heaters, etc. can impact their operation.

Air is a lot like most people in that it takes the path of least resistance.  So, air coming through leaks can mess with the home’s return air system.  For a heating and air conditioning system to work properly, adequate air of a certain temperature has to be supplied to an area to compensate for the heat gain or loss from that area.  What may no be known is that air has to also be removed from the area to help the supply air side of the system work right.  In buildings with poor return air systems, large temperature differences could exist from one area to another even if the supply air flow is ideally designed and installed.  What can happen is that air entering through leaks has the path of least resistance to the air handler.  That air, then, prevents the return air system from returning air back to the air handler from some (or all) of the building’s areas.  Those areas that do not have proper air return will be hotter or colder, depending on whether the air handling system is in the cooling or heating mode, respectively.  Alternatively, those areas through which the leak air is traveling could be too hot or too cold.

What about buildings that are pretty well sealed?  If the exhaust fans in the home do not have adequate makeup air, they will either not move as much air as designed or makeup air will come from wherever it can, which might be from undesirable places, such as through flues or chimneys.  The condition of air flowing in the reverse direction from which it is intended is called backdrafting.  When backdrafting occurs in flues and chimneys, combustion gases, including carbon monoxide, could be pulled into the home.  When wood is not being burnt in the fireplace, backdrafting air can pull creosote emissions into the home, which believe me is not a desirable fragrance. Backdrafting can also impact combustion of some appliances, making them less efficient.

What if a combustion appliance, such as a water heater or furnace, have flue booster fans that are supposed to push the exhaust gases outdoors.  If the appliance is a closed system, such as many of the higher efficiency furnaces, no impact should be expected because closed systems pull air directly from outdoors.  Appliances that pull air from the general building air, as do the water heaters with flue fans, may be affected, depending on which fan in the building moves more air or other characteristics.

The impact that exhaust fans could have on other combustion appliances is not unknown to building professionals, though.  Some homes with furnaces that used general home air for combustion have a duct that runs from outdoors to somewhere in the vicinity of the furnace.  That is all.  This duct is not connected to any fans or any other devices.  This duct is simply a path for air to travel from outdoors to indoors to makeup air removed from the home.  Do they work?  Maybe.  But, as I said earlier, air takes the path of least resistance and, if the duct is not the path of least resistance, it will not work.

The concern as stated in the blog post cited at the beginning of this blog in particular was discussing the installation of large kitchen exhaust fans that move over 1000 cubic feet per minute (cfm) of air.  That is an extraordinarily large fan for a home.  Will the usual kitchen exhaust fan cause the same issues?  If it doesn’t exhaust air outdoors, which is normal for these fans, the answer is most likely no.  If the fan exhausts air outdoors, the answer is maybe.  By itself, the fan likely will not cause backdrafting at the least.  That fan in combination with other fans might cause backdrafting.  Again, if the home is air leaky, any exhaust fan can pull air through leaks, causing thermal comfort and/or heating or cooling efficiency issues.

Are exhaust fans the only things that can cause air leakage or backdrafting issues?  Well, no.  All buildings have a chimney effect where heated air rises within the building.  As this air rises, air is pulled into the building at lower levels.  The chimney effect is for the usual home is definitely not as great as that for a high rise building.  In most homes, backdrafting due to the chimney effect is likely not an issue; but the chimney effect can cause drafts in lower parts of the home.  The only way to know whether a backdrafting or draft issue exists is through investigation.  A homeowner might be able to investigate the issue using smoke from an incense stick or other air flow indicator.   However, a professional will know more about the conditions to which to test under and will have more sophisticated instruments than a homeowner.

So, if you have this favorite nook in your home that sometimes feels comfortable and then other times feels drafty, consider that the reason could be an exhaust fan or the home’s air handler pulling air through a leak.  What to do about it from there is up to you.

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The warning bears repeating again, again and again

September 19, 2010

The warning bears repeating again, again and again.

The on-line version of the Chicago Sun Times carried this story today:

Infant drowns in water pail

http://www.suntimes.com/news/metro/2725352,CST-NWS-baby19.article

In a previous post (https://criteriumincincinnati.wordpress.com/2009/12/02/a-sobering-reminder/), I discussed another infant drowning in a sump pump pit.  Granted, a drowning in a sump pump pit is a pretty rare event, especially since sump pits usually have lids that are supposed to be used with them.  In the case of the infant in the Sun Times article, the culprit is a common water pail.

But, water pails are not the only potential downing locations.  Every adult who is responsible for watching kids should know about the drowning potential of bathtubs, sinks or other bathing facilities.  What about toilets?  As I stated in the previous post and will repeat here, infants and toddlers can drown in only a few inches of water.  Exasperating the drowning potential is the fact that infants and toddlers are head-heavy.  If they fall into a container of water head-first, they likely will not be able to get out of the container, whatever it is.

Containers are not the only potential drowning places.  Fountains, pools, ponds, streams–any body of water should be off-limits to infants and toddlers.  If they are mobile, they are not the steadiest people on their feet.  On visits to Fountain Square in Cincinnati, I have watched many parents let their young ones walk on the lip of the various parts of the fountains.  I have to wonder what are those parents thinking.  What would happen if they looked away for a short time or could not make it to the fountain in enough time.

Apparently, the City of Cincinnati thought about this issue because the main fountain now has a low fence installed along the inside lip of the large fountain.  My son thinks it is because of other reasons, such as adults using the pool for other means.  Even still, maybe Cincinnati helped resolve another potential issue at the same time.

If you are a child’s caretaker, don’t just react.  Anticipate if you can what the child is going to do.  And take stories like the one in the Sun Times as a warning and be educated.

A sobering reminder

December 2, 2009

The following news item was released on December 1, 2009:

3-Year-Old Ind. Girl Drowns In Basement

FORT WAYNE, Ind. (AP) — Authorities say a 3-year-old Fort Wayne girl drowned after she fell into a sump pit pump pit in her family’s basement.

The Allen County coroner says Alexis Stark-Bork was pronounced dead at a hospital soon after she was found in the pit about 2 a.m. Saturday.

Police say Alexis was last seen watching television in the home’s living room. About 20 minutes later, the girl’s parents noticed she was missing and she was found face down in the pit.

An officer reported finding the pit’s cover about 6 feet away underneath a futon.

(Copyright 2009 by The Associated Press. All Rights Reserved.)

What a sobering reminder.  I have heard of drownings where a toddler has fallen head first into a regular 5-gallon bucket.  I never thought about a sump pit system, even though a sump pit is a bucket of sorts.  In fact, I have seen cases where a regular 5-gallon bucket was used for one.  A sump pit holds water like a bucket; but, unlike a bucket, when enough water builds up in the sump pit, a float switch is supposed to activate a pump that empties the water.  Even though the lid not being on the sump pit appears to have been the reason this child drowned, other issues could be involved.  For example, even though the toddler would have raised the water level in the sump pit, why didn’t the float switch activate the pump and lower the water to a safe level.  Likewise, I have also experienced many other cases of problematic sump pit systems, which before I would have only considered as potential moisture problems. Now, I see them as potential safety problems too.

First and foremost, sump pits are supposed to have lids.  That point is pretty obvious in this toddler’s case where the lid was not used.  The obvious lesson is to make sure that if the sump pit has a lid, USE IT.  Sump pits can be deceiving.  When water is not flowing into the pit, seeing the water in the pit can be difficult for an adult–and probably impossible for a toddler.  In fact, in my own sump pit, I have to check the position of the float switch sometimes to determine whether water is in it.  One particular time stands out in my mind when the float switch failed to activate the pump.  The sump was filled to the brim and I could not notice it until the area around the put got wet.

Furthermore, I know of at least three sump pit designs and I would be very safe in assuming many others exist.  The various sump pits do not have interchangeable lids.  Therefore, make sure to use the right lid for the sump pit.

That is not the end of the discussion, however.  Manufactured sump pits have a rim specifically made for a lid.  Homemade sump pit systems, such as 5-gallon buckets or plastic barrels, don’t.  Someone will likely argue that the latter have lids.  However, when their lids are cut to allow access for the plumbing, they are likely not structurally able to bear the same weight as the manufactured lid.  I have seen a variety of lids that were well constructed and possibly could work as well as the lid manufactured for the sump pit.  More often, I have seen lids that are not well constructed.

But, let’s assume that the lid is well-constructed, the most common material I have seen used is plywood.  So, let’s see, a wood product being used over a sump pit that contains water or is in a moist environment.  Over time, the wood can rot (and I have also witnessed that), rendering the lid useless as a safety device.

The bottom line is that homemade sump pit lids do not meet safety codes—so, just don’t use them.  Likewise, manufactured sump pit lids are not made to be used on homemade sump pits.  So, don’t use homemade sump pits.

Someone will likely argue that if sump pit is not located in basement where a child can find it, why use a manufactured sump pit, right?  Any parent or other person who knows kids will tell you that kids don’t always go only where they should.  Again, just use the right sump pit and lid for the job.  If that argument is not reason enough for some people consider this point.  If a person does use a lid that is designed for the sump pit or uses a sump pit that was not designed for safety, although I am not a lawyer, I can see where that person probably has just surrendered pretty much any legal defense.

Assuming that the correct manufactured lid was used for the correct manufactured sump pit, another factor to consider is that manufactured lids have a locking mechanism on them.  The more expensive sump pits, particularly those used with radon mitigation systems, have lids that have fasteners, such as screws.  The most common, and generally least costly, types of sump systems have a lid that twist-locks on the sump pit.  With these types of sump systems, the lid and sump pit rim have tabs.  The lid is inserted into the rim of the sump pit with the lid’s tabs misaligned with the sump pit’s tabs.  The lid is then twisted so that its tabs slide under the sump pit’s tabs, locking the lid in place. If the sump pit does not have a locking lid, get another system that does have one.

Even with sump pits that have locking lids, many times I have found the sump pit lid only sitting inside the rim and not locked.  In some cases, twisting the lid to lock it is not possible because the concrete around the sump pit lid had pushed the rim inward; making the lid/pit fit so tight the lid cannot be turned.  The lid should be set in the sump pit rim when the concrete is put around the sump pit during the pit installation.  Further, before the concrete sets, the lid should be twisted back and forth to assure that is will work properly.

Even if the lid fits and can be twisted, I have found many cases where the pipe from the sump pump prevents the lid from being fully locked.  For twist-lock sump systems, the pipe is usually supposed to be installed so that it is centered in the sump pit.  Manufactured lids have a slot that fits around the pipe, so that the lid can be set in place around the pipe.  When installed properly, the pipe is at the end of the slot in the lid, and the lid can be twisted and locked.  If the pipe is not centered in the sump pit, but is installed more toward the rim, the lid can only be twisted with difficulty or not at all.  Therefore, be sure to test the pipe installation to make sure the lid works before the pipe parts are glued or cemented together.  Check twice, glue once.

Speaking of plumbing, somewhere in the plumbing system, a check valve should be installed to prevent water in the pipe from re-entering the sump pit.  In most basement sump pump installations, the pipe runs vertically a number of feet before it turns horizontally to exit through the foundation wall to points thereon.  When the sump pump empties water from the pit and then turns off, all of the water in the vertical pipe can flow back into the sump pit due to gravity.  As the water in the vertical section flows back down the pipe, the water can also siphon water back from horizontal pipe sections.  A check valve allows the water to only flow in one direction–up the pipe.  With a check valve in the plumbing system, when the pump shuts off, water cannot flow back into the sump pit.

Without a check valve, a sump pit can partially, and in some cases fully, refilling after the pump shuts off.  Least case, the pump constantly cycles trying to empty the sump pit because the pit refills as soon as the pump shuts off.  The worst case is where a potential drowning situation could occur if the sump pit only refills so that several inches of water are in the pit, but not enough for the pump to be actuated.

Even if a check valve is installed, they sometimes fail, such as when grit in the water causes the valve to get stuck open.  So, first, make sure that a check valve is installed in the plumbing.  Usually, one is installed right at the pump or within a few feet of it.  In most cases, the check valve must be in a vertical position to work correctly.  For those who are not sure what a sump system check valve looks like, I recommend taking a trip to the ol’ Home Depot to see what one looks like.  Although they may vary in appearance, they normally have the same shape or markings.  If a check valve is installed, do not fully trust that it is or always will be working.  Periodically, operate the sump pump to the point where it shuts off.  When the pump stops, check to see if water is flowing back into the sump pit.  A little likely will back flow; but a lot indicates a check valve problem.

On the other hand, another problem I have found is where the float switch or pump is not working properly.  Float switches do fail, and one could fail so that the sump has adequate water in the sump to drown a child.  Usually, people do not discover that a float switch has failed until a basement floods or other moisture problems occur.  The lesson here is to periodically check the sump pump float switch by elevating it to the point where it activates the pump.  Check to make sure that the pump continues to operate until the sump pit is nearly empty.  By the way, be sure to use a non-conducting material, such as wood, to lift the switch, just in case an electrical “leak” has energized the water.

When the float switch fails, a person has three alternatives to fix it.  The first one is to replace the pump and float switch as a unit, which is how they are usually sold.  The second alternative is to replace the switch, which is tricky for most home owners because the switch needs to be watertight to prevent an electrical short or worse an electrical leak that energizes the water.  If the home owner is not extremely handy, the pros should replace the switch.

The final alternative is to install a float switch parallel to the one that is not working.  The problem that occurs with this installation is that the float switch might not be adjusted properly.  Manufacturers of pump/switch assemblies preset the distance of travel for the switch relative to the pump.  When installing a replacement float switch in parallel with the old one, the installer needs to manually set this distance.  That setting can vary widely depending on how the switch is installed.  The problem is that if the switch has too much travel, the sump could have more than enough water to drown a toddler.

Just as likely as float switch failure, though, sump pumps also fail.  I had one case of a basement flooding where the sump pump was literally encased in minerals from the water.  In areas like southern Ohio, which has high mineral content in the water, concretions like this case can occur.

Grit carried into the sump pit with the water will also eventually doom most pumps.  The impellers on most pumps are normally plastic, and the grit can chew them up.  In some cases, the grit or even pieces of plastic from a degrading impeller can jamb the impeller, causing the pump to fail.  I recommend that the sump pit pump be set up off the floor of the sump pit a couple of inches to provide a grit settlement area.  A brick laid flat provides just about the right distance above the sump pit floor for this purpose.  The grit in the settlement area should be cleaned out ever year or so because this area can fill with grit where it can once again get into the pump.

Another electrical problem that can occur with sump pumps is that some codes require that they be installed on a ground fault circuit interrupter (GFCI) outlet or circuit.  Based on personal experience, a GFCI can kick out for some unknown reasons that have nothing to do with a short.  Most people do not discover that the pump is not working, again, until a basement floods or other moisture problems occur.  I recommend that most people install a battery-backup sump pump.  Until now, that recommendation was based merely on the threat of a basement flooding.  I now have another reason for that recommendation.

Even when a float switch or pump has failed, water can back up and pool below a basement slab, hiding for a time the fact that the sump system is not working.  Further, for most homes, periods can occur where the sump pump does not work frequently, leaving the sump pit with adequate water to drown a toddler.  In most cases, home owners treat sump systems as an out of sight, out of mind item.  They should not be.

The sad fact in the case of this toddler’s downing is that a thing as simple as the lid may have been the most important factor in saving her life.  Even if the float switch and sump pump were operating as intended, the toddler could have fallen into the sump on top of the float switch.  In which case, she could have submerged the switch, preventing it from actuating the pump.  If she had fallen in such a way that the sump’s water level was raised enough to allow the float switch to activate the pump, the water might have been lowered enough for her to survive.  No matter what, a lid would have prevented her falling into the sump.  And, I have seen my share of sumps that did not have a lid installed.

Even if the sump pit has a lid, if it is located in a room or closet away from the rest of the basement, make sure that room or closet has a door with hardware that a toddler cannot operate.  If the sump is located in a crawlspace, make sure the crawlspace is not accessible to any children.

Up to this point, I have covered all of the mechanical aspects of how problems with a sump pit system could have contributed this toddler losing her life.  Now, I will put on my other hat as a father (whose kids are now all grown) and a former volunteer EMT.  A toddler can drown in less than four minutes and in only a few inches of water.  If they fall head first into a bucket, or in this case, a sump pit filled with water, they do not have the upper body strength, or even know how, to get out of the situation.  A toddler’s weight distribution is different than an older child in that they have more weight distributed toward their upper bodies.  In effect, they are top-heavy.  Once head down in the water, they would have a very difficult time getting out of it and definitely not able to call for help.

This leads to the most important lessons of all.  A parent should constantly be evaluating the home for potential safety problems for kids.  I encourage all parents to take available kid safety classes when they are offered and freely exchange kid safety issues whenever they hear them.  While some aspects of homes remain fairly constant, designs, materials and systems are constantly changing.  My grandparents began their lives in homes that did not have electricity–now, it is all around us in our homes.  If you do not know about child safety in the home, here is a good place to start:  http://www.homesafetycouncil.org/index.asp.

I will close this final lesson, and it is one that most parents have heard before.  Always know where your kids are.  For toddlers, always have them within sight or hearing range.  Train yourself to listen for when they are not within site.  Most parents do; but the important skill is to make sure you keep attentive.  Drowning can occur in less time than a phone call.  If you don’t hear your child and you know they are not napping, then check up on them.  Always be in touch with them somehow.  Remember, less than four minutes can be the difference between you watching your child grow up or your having a lifetime of regret and guilt.


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