Tempered Glass Saves Lives

June 1, 2020 in Glass, Injury, Safety, Tempered Glass

This past Sunday, May 31, 2020, marks another day in United States history where peaceful demonstrations and orderly civil disobedience were highjacked by unlawful activity leading to property destruction and theft. The author’s Bixby Knolls, Long Beach, California neighborhood was thankfully sparred wide-spread damage.

Tempered Glass

Tempered Glass Saves Lives

This article is not about the political reasons for the nationwide demonstrations.  Instead it concentrates on something that television coverage and social media have not reported. Specifically, how advancement in glass safety has reduced the number of people being injured due to broken glass.In fact, we will never know how many of the looters and bystanders, including police and national guardsman, were able to escape what could have easily been a significant number of bodily injuries from glass shards and glass debris used as weapons.

In the television broadcasts viewed by this author none of the glass storefronts being damaged or destroyed showed human blood from cuts by broken glass.  This is due to the major change in building codes decades ago requiring all commercial glass to be either of the wire safety type or tempered.  Again, from television broadcasts the evidence indicates that all the broken glass shown was of the tempered type.

Here is a short tutorial regarding tempered glass:

Tempered glass is also referred to as toughened or sometimes as fully tempered glass.  The glass sheets are heated to around 1,148℉. They then undergo a high-pressure cooling process called quenching.  This process, which only lasts between 6 to 10 seconds, blasts cool air from various positioned nozzles onto the glass surfaces which cools the outer surfaces of the glass much quicker than the center. As the center cools down it tries to pull back from the outer surfaces resulting in the center remaining in tension while the outer surfaces go into compression which gives tempered glass its high strength. Tempering can also be achieved with chemical treatment but it is far more expensive than quenching and not widely used commercially.

When damaged tempered glass breaks into smaller granular pieces (as can be seen in the image taken of one of the targeted stores near the author’s home) as opposed to large jagged shards of non-tempered glass.  These smaller granular pieces are less likely to cause bodily harm.  The high strength of tempered glass and its high safety record is why you also see it being used in shower and tub glass enclosures, microwave ovens, refrigerator trays, glass table tops, and more.

We can all be thankful to the scientists, engineers, and the many manufacturers of glass products for making our communities safer.

Hot Water Scalding

May 18, 2020 in Hazard, Hot Water, Injury, Safety, Scalding, Temperature

Perhaps one the least analyzed area of personal injury has to do with the causes of burns due to scalding by hot water. The temperatures which lead to burns differ between age groups and the ways to control of those temperatures are often overly generalized.

For instance, in the International Plumbing Code (IPC) (2018 IPC 412.10)   for shower, hot tub and head shampoo sink faucets water temperature is specified to not exceed 120℉ (2018 IPC 412.3 & 412.5). Anything above that temperature is considered to be a hazard. However, the code is incomplete because it is silent as to how long can, or should, a person expose themselves to a temperature of 120℉.  Anyone who has spent any time in a hot tub knows that your body is somewhat comfortable in temperatures in the 90’s but once you extend into the 100’s your duration in that hot tub diminishes with each degree rise in temperature.

We also need to understand that going too far below the 120℉ temperature could expose us to the dangerous Legionella bacteria well known to cause Legionnaires’ disease. According to the Centers for Disease Control and Prevention (CDC) (//www.cdc.gov/legionella/wmp/overview/growth-and-spread.html) this bacteria occurs naturally in a variety of fresh water bodies such as lakes, rivers and streams where the bacteria is in relatively low amounts and not likely to cause a health hazard. The same cannot be said for the bacteria residing in the plumbing systems of either residential or commercial buildings. Legionella bacteria thrives in such systems with temperatures between 77℉ – 108℉. It is therefore imperative that our hot water storage and delivery systems control the temperatures above or below that range of temperature but as of this writing they do not.

Some may ask if the hot water temperature can be controlled with the thermostat setting found on the hot water tank or today’s tankless water heaters.  The short answer is only to the degree of it’s maximum heat and therefore should not be relied upon for safety settings.  IPC 501.6 requires that “the temperature of water from tankless water heaters shall be not greater than 140℉ where intended for domestic uses”.  That leaves a 20 degree difference between the required maximum and the heating capacity of the water heater. Furthermore, standard water heaters do not have a set maximum water temperature. In fact, in some States such as California the plumbing code is clear that “The water heater thermostat shall not be considered a suitable control for meeting this provision” (provision meaning controlling the temperature coming out of the spigot at a maximum of 120℉) (2016 California Plumbing Code[CPC] 407.3). The mechanics of controlling the temperature beyond the water heater thermostat is a discussion we will tackle in a follow-up article. For now, we can say that a simple hand held thermometer is a simple first step by property owners and tenants to check the delivery temperature of the water.

Currently the codes are silent on the temperature delivery for hot water at a sink or lavatory in a private building such as a house or apartment. They only mention a maximum 120℉ range is for “Public Lavatories” (2016 CPC 407.3).  Those would logically include places such as hospitals, restaurants, airports, gas stations, and other places where the “public” has access to lavatories. What about domestic and commercial kitchen sinks? As of the date of this article the plumbing code is silent.

So we see what the plumbing codes say but in this author’s opinion that is not sufficient to prevent scalding or to truly understand what the consequences are when deciding how to approach burn associated cases involving hot water.

According to the American Burn Association – Scald Injury Prevention – Educator’s Guide:

Young children have thinner skin resulting in deeper burns than adults for the same temperature and exposure time to a scalding substance. The proportion of a child’s body that is exposed to any given amount of a scalding substance is also greater: the same cup of spilled coffee will burn a much larger percent of a small child’s body. Small children also have little control of their environment, less perception of danger and less ability to escape a burning situation on their own. Children grow fast and can reach new, dangerous things every day. They do not realize that hot liquids burn like fire. 

The Guide provides the following basic table for how hot temperature can affect a human being: 

In addition, according to an article by the Regional Medical Center at Memphis, National Burn Awareness Week February 6 – 12, 2012 the tolerance for exposure of hot water to infants and seniors is shorter than that noted in Table 1 above,

A further analysis of the two tables reveals a conflict between what the experts believe is a “Safe for bathing” temperature and the warning that any temperature below 108℉ could cause exposure to the Legionella bacteria. So are we exposing persons to danger of an illness when setting the temperature at or below the otherwise safe 104℉?  And, what is the “time for 3rd degree burn to occur” between 108℉ and 119℉?  It will likely be less than five minutes but the exact time data is not provided.

Some may argue, especially as it relates to small children, that children must be controlled by a supervising adult at the time the child is exposed to normal bathing activity.  It is assumed that most parents, guardians, or other such supervising adults would know not to place a child in a tub filled with extremely hot water. They may not know the exact temperature but most adults can feel the difference between safe and not safe water temperature. On the other-hand children are known to slip away from the guardian eyes of an adult and could cause themselves harm because of their playful or inquisitive nature.

In conclusion, no matter which side you are on Plaintiff or Defense, the scalding of humans by hot water is definitely a concern and must be taken seriously. Children’s accidental burns are heartbreaking and emotions can cloud our vision. As experts we need to rely on the science and follow the evidence wherever it may take us.  While this article may lead you to believe that lowering the temperature of hot water is the only answer, reducing the temperature to a level where the temperature range can lead to unwanted and unhealthy bacteria growth is also not the answer. The only clear mechanical answer is to design and install a system appropriate for the use and location.

In the meantime, Safe Kids Worldwide (www.safekids.org) and the American Burn Association (www.ameriburn.org) suggest ways for adults to 

Prevent Scalds During Bath Time:

  1. Set water heater to a maximum temperature of 120 degrees Fahrenheit or just below the medium setting (presumably giving under five minutes of time to pull a child out of a too hot tub)
  2. Check bathwater temperature. Before placing child in the bath, check the water temperature with your elbow (other source) or the inside of wrist as is done with heating baby’s milk. The water should feel warm to the touch, not hot.
  3. Place child in the bath facing away from the faucet. This way they won’t be tempted to touch the hot faucet or turn on the hot water.
  4. Do not leave a child unattended.

A single article cannot answer all the questions about hot water the its consequences.  Commercial, industrial, food industry, health care and other such faciilies vary greatly in the need and standards for each of those industries. Each must be examined for its unique need, use, and safety protocols.

Machine Guarding

January 3, 2020 in Hazard, Injury, Machine Guarding, OSHA, Safety

Industrial and manufacturing plants and assemblies are closely associated with machine guarding as an element for protection of workers and those around them.

Machine guarding is one of the essential elements that concerns industrial and manufacturing plants. Machines that fall into the category of guillotine cutters, shears, alligator shears, power presses, milling machines, power saws, jointers, forming rolls and calendars, and various portable power tools are just some of the basic machines that require guarding. 

In California Cal-OSHA machine guarding requirements are found under Subchapter 7. General Industry Safety Orders, Group 8. Points of Operation and Other Hazardous Parts of Machinery 

Article 54. Scope and General Definitions, Section 4184 which states the following:

(a) Machines as specifically covered hereafter in Group 8, having a grinding, shearing, punching, pressing, squeezing, drawing, cutting, rolling, mixing or similar action, in which an employee comes within the danger zone shall be guarded at the point of operation in one or a combination of the ways specified in the following orders, or by other means or methods which will provide equivalent protection for the employee.

(b) All machines or parts of machines, used in any industry or type of work not specifically covered in Group 8, which present similar hazards as the machines covered under these point of operation orders, shall be guarded at their point of operation as required by the regulations contained in Group 8.

Exception: Microtomes (also called histotomes or cryostats) when guarding as required in Section 4184 is infeasible and the microtome is used, operated and maintained in accordance with Section 3558 of these Orders. For the purposes of this Exception guarding as required in Section 4184 is infeasible under circumstances that include, but are not limited to the following: there is no point-of-operation guard commercially available for an employer’s microtome.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.

Similar language is found in the United States Department of Labor Occupational Safety & Health Administration guidelines for machine guarding Section 1910.212(a)(1):

Types of guarding. One or more methods of machine guarding shall be provided to protect the operator and other employees in the machine area from hazards such as those created by point of operation, ingoing nip points, rotating parts, flying chips and sparks. Examples of guarding methods are-barrier guards, two-hand tripping devices, electronic safety devices, etc.

It is important to note that machine guarding alone is not sufficient when maintaining any equipment.  Proper Lockout, Tag-out, or Block-out protocol must be followed.  A July 2019 publication by Cal-OSHA noted the following:

Failure to lockout, tag-out, and block-out (LOTO) machinery before working on it is a major cause of serious injuries and deaths. Workers can be electrocuted, suffer severe crushing injuries, and lose fingers, hands, and arms because machinery is inadvertently turned on while it is being cleaned, repaired, serviced, set-up, adjusted, or unjammed.

(For more information see Cal-OSHA Subchapter 7. General Industry Safety Orders, Group 2. Safe Practices and Personal Protection, Article 7. Miscellaneous Safe Practices Lockout / Tag-out / Block-out, Section 3314)

The author started to work with heavy machinery dating back to the early 1970’s.  The nearly 50 years of hands on experience, numerous installations, and scores of investigations, in addition to certifications and licenses, has provided the type of experience that allows the author to provide expert opinions regarding machine guarding and other industrial safety topic. 

Why Does Fall Protection Count?

August 28, 2019 in Cal/OSHA, Fall Protection, Falls, Hazard, Injury, OSHA, Roof, Safety, Slips

In a perfect scenario as illustrated in the attached photos we see a roofer standing at the edge of a parapet.  The roofer has no fall protection of any kind.  Give the roofer credit for wearing protective clothing necessary as a means to protect his body while applying a coating over a spray foam roof, but that protective suite will not stop him from falling.

The distance from the top of the parapet to the ground is approximately seventeen (17) feet.  The ground below is a hard surface which would be unforgiving to a falling human body.

A slight slip of either feet. A tangling of the boots in the protective covering. A sudden distraction. A sudden gust of wind. All of these situations can cause the roofer to loose his balance and fall to the ground below.

Beyond any OSHA requirement, and the obvious serious injury or even fatality which would result in the roofer falling to the ground below, the shock and grief that will affect to his fellow roofers, family, and friends is beyond measure.

It is for all the right reasons, and logical conclusion, that fall protection is a necessary safety measure. The code allows a number of ways to protect the roofer or anyone else working above ground.  Simple steps can reduce the risk of injury and prevent long term disability and even death.

When Fall Protection Means Saving A Life

Dangerous Behavior

August 13, 2019 in Cal/OSHA, Fall Protection, Falls, Hazard, Injury, OSHA, Safety

It goes without saying that standing in the bucket of an excavator to hang a sign is not a good or safe idea. Such behavior is not only unsafe but also violates California General Industry Safety Orders, §3657 – Elevating Employees with Lift Trucks (Fed OSHA §1910.67). 

According to the United States Department of Labor OSHA (osha.gov) “Many workers are injured or killed on aerial lifts each year”. Currently an aerial lift is described as one of the following:

  • Extendable boom platforms,
  • Aerial Ladders,
  • Articulating (joined) boom platforms,
  • Vertical towers, and
  • Combination of the above

The bucket of any excavator does not fit the definition of an aerial lift.

According to OSHA (osha.gov) even if someone properly uses an aerial lift the hazards for using such equipment may include: 

  • Fall from elevated level,
  • Objects falling from lifts,
  • Tip-overs
  • Ejections from the lift platform,
  • Structural failures (collapses)
  • Electric shock (electrocutions),
  • Entanglement hazards,
  • Contact with objects, and
  • Contact with ceilings and other overhead objects

As illustrated in the photo below the gentleman is hanging a warning sign while standing inside the bucket of an excavator. How ironic that someone is hanging a warnign sign considering the unsafe behavior being exhibited.  

You Should Never Do This

In the instance of hanging a warning sign a safe practice would be to use a properly designed ladder supported by solid footing.  Solid footing in this case would have been a smooth, level, and solid ground.