Topic: Building & Life Safety

Modular home on home

The problems with modular homes: Built to burn?

When we discuss the problems with modern methods of construction, mainly lightweight/engineered wood components, we usually think about the site-built homes. In a Fire Engineering article Chief Kevin Gallagher of the Acushnet (MA) Fire & EMS Department considers the problems of modular homes, which are factory-built and then towed in sections to be installed at a permanent location, and range from “simple capes to multibox McMansions.” The chief recounts a fire in a two-story, prefabricated/modular residence in 2008 and says; “Despite our department's best efforts, the structure was a complete loss…we never had a chance to save it. Fox Boston covered the fire incident in a previous report. He tells us that research to learn about the methods of construction used by the modular industry has been the subject of several other Fire Engineering articles. He says very serious concerns were discovered; mainly:”large void spaces between levels of habitation, the use of flammable adhesives as the sole means of attaching gypsum to wood ceiling joists, and the presence of holes used to assist in lifting modular boxes onto the foundation, which can create an easy pathway for fire spread.” He adds; “Our goal has been two-fold. First, we identify the flaws with the construction methods used. Second, we fight for change through the code development process. Third, we spread the word to any and all fire service members of these hazards and the tactical changes the hazards require.” The problem was documented in a Fox Boston report. Chief Gallagher concludes; “Do we have a problem? My answer, since the moment I pulled up on a fire in a modular structure, is an emphatic YES! My sense is that those firefighters who have dealt with fires in these types of buildings would agree.” He says he will “dig deeper, share valuable information and, hopefully, provide you with an awareness and appreciation for the hazards within modular construction” in the following months. Although Chief Gallagher does not talk about fire sprinklers as a way to offset the problem in this particular issue, it should be a major consideration for home fire sprinkler advocates. Get a free copy of the dangers of lightweight construction presentation.

Seven workers die in Confined Space Accident at Corona Brewery

Well, my confined space blog may have slowed down a bit in the past couple months due to other ongoing work, but unfortunately the confined space fatalities have not slowed down... In April, seven workers were killed in a tank that was undergoing maintenance and cleaning at a plant in Mexico City operated by Corona beermaker, Grupo Modelo.  It is believed that four victims were maintenance contractors and three victims were other Modelo employees.   There are few details available on the incident.  It is speculated that the deaths were due to “unspecified toxins” and that the three Modelo employees had entered the tank in an effort to rescue the other four contract employees.   Mexican authorities are reportedly investigating the incident.   Confined spaces are or should be clearly recognized in the beer industry.  The large numbers of tanks that are entered for maintenance and cleaning, combined with hazardous atmospheres including carbon dioxide produced during fermentation, inert atmospheres, and ammonia from refrigeration systems creates significant confined space entries and hazards.   These incidents do not just happen in foreign countries, and wine makers are also not off the hook when it comes to confined spaces.  A confined space death occurred just two years earlier at Napa California at Ancien wines when a worker was overcome by nitrogen and argon gases inside a tank.   Workers entering into tanks in the beer and wine industries should be intimately familiar with confined space entry procedures.  Even if contractors were always used to perform confined space entry work, it is unclear why Modelo employees would have entered the tank if they had been trained to recognize the confined space hazard.  The Modelo company has been in operation since 1925 and is the maker of the number 1 imported beer in the United States.  This confined space incident has the largest loss of life in one entry that I am aware of.  While it is not uncommon to lose 2-3 workers, this incident claimed the lives of 7 workers.  Confined space entry hazards continue to claim lives despite improved recognition of the hazards and despite regulations and guidelines available to prevent such incidents.   The National Fire Protection Association is developing a Best Practices document for confined space entry. This document will address gaps in existing standards and will be more prescriptive in describing things like how to test the atmosphere in and around confined spaces prior to entry.  The NFPA document is looking to go beyond the minimum standards and to provide those looking to develop a “gold star” confined space entry program with the information they need to do so.  Please email me at for further information and/or leave a comment below for discussion.  I look forward to hearing from you!

FAQ Friday, NFPA 80 - Can labels on fire doors be painted?

Labels on fire doors, fire door frames, or other components of a fire door assembly, are the identifying mark that the door or component has been tested to the required first test standards and has passed the criteria required by those test standards.  Labels prove to inspectors, AHJs, building owners, or anyone else observing the fire door assembly that it (as tested) will protect the opening as it did when tested. NFPA 80, 2013 edition, contains the following language regarding labeled products: 4.2.1* Listed items shall be identified by a label. 4.2.2 Labels shall be applied in locations that are readily visible and convenient for identification by the AHJ after installation of the assembly. Associated annex language to Section 4.2.1 sheds some light on the intent of the labeling provisions in NFPA 80: A.4.2.1 Labels can be permitted to be of metal, paper, or plastics or can be permitted to be stamped or diecast into the item. Labels should not be removed, defaced, or made illegible while the door is in service. If the label on an existing fire door has been removed or is no longer legible, it is acceptable to verify the rating of the fire door through other means acceptable to the AHJ such as an inspection or certification service that provides acceptable documentation. One of the most frequently asked questions that I received regarding labels is whether or not they can be painted.  Paint most often will render the label illegible, thus it is not recommended that labels be painted.  Proper training and education should be provided to those in buildings who may be doing repair or maintenance work to doors to ensure they are aware of the risks associated with painting fire door labels.  Labels are required in a number of applications on all types fire door assemblies. Where NFPA 80 mandates a label be present, it should meet the requirements of Chapter 4 as noted above.
Fire damper

FAQ Friday, NFPA 80 - What is the inspection and testing frequency for fire dampers?

As the name implies, NFPA 80 provides requirements for more than just fire doors. The installation, inspection, testing, and maintenance of other opening protectives such as fire windows, glass block assemblies, fabric fire safety curtains and fire dampers are also included within the scope of NFPA 80. Three editions ago (2007), the requirements for the installation, inspection, testing, and maintenance of fire dampers were moved from NFPA 90A to NFPA 80.  One of the questions I get asked most often is with regards to the inspection and test frequency of fire dampers. Like all opening protectives, continued maintenance and inspection is critical and will help ensure that the doors, windows, shutters, dampers, etc.  will operate properly under fire conditions. First, an  operational test must be completed after the installation of the fire damper is complete. Then, each fire damper must be tested and inspected one year after the installation. After that one year mark, fire dampers must then be tested and inspected every four years except for hospitals which have a six year frequency. This begs a follow up question:  why the difference in the testing and inspection frequency between hospitals and other types of building uses? Most users expect provisions related to hospitals to be more restrictive than for other types of buildings. The healthcare industry presented the technical committee with significant evidence that a four-year inspection frequency for fire dampers in hospitals, in these buildings, is a hindrance. Hospitals are unique in that they have many building systems critical to the life safety and health of their occupants (patients). Personnel accessing fire dampers every four years would entail the risk of interfering with or potentially damaging the many systems (HVAC, medical gas systems, sprinkler piping, electrical systems) that are located near the fire dampers and above ceilings. The six-year frequency allows for a reasonable but safe length of time between inspections and also ensures the integrity of the hospital operations. Additional details regarding the inspection criteria and documentation can be found in Chapter 19 of NFPA 80.
Wind turbine

Wind turbines as confined spaces

Typically we think of climbing down into tanks, vaults or manholes for confined space entries.  Most would not think of wind turbines as having confined spaces.  Large enough to enter and perform work, restricted means of entry or egress and not designed for continuous human occupancy…. Wind turbines clearly have components that meet the definition of a confined space AND they have potential hazards.  With the push towards green energy, wind turbine installations are increasing rapidly.  In 2012 wind energy became the number one new energy source, with over 45,000 wind turbine installations currently in the U.S., according to AWEA (American Wind Energy Association).   Photos: While green technology may be good for the environment, it is not without hazards to the workers who install and maintain the technology.   As OSHA indicates on their Green Job Hazards webpage, “Green jobs are not necessarily safe jobs”. Hazards for workers in wind turbines include falls, electrical, mechanical, fire, and confined space hazards. Both OSHA and AWEA have pointed out the need for confined space training of wind turbine workers.   Confined spaces exist during construction and after installation of the turbines.  There are four main components that may be considered confined spaces; the tower (vertical support), the nacelle (the housing that contains the electrical components) the hub (hub attaches to nacelle) and the blades (attach to hub).  During construction of the turbine workers may need to enter sections of the tower, nacelle, hub or blades to finish seams, grind, paint, etc.    When fully installed, workers need to climb up the tower to reach the narrow, restricted spaces of the nacelle, hub and blades for maintenance, inspection and repairs.  Electrical hazards have been the source of a number of fatalities and fires in wind turbines within the confined spaces.   An electrical incident or spark that occurs in the nacelle can quickly engulf a worker whose only way to exit the space is to descend a several hundred foot ladder or to climb on the roof of the nacelle. Some nacelles are made with polystyrene type foam which is extremely flammable and adds to the fire risk.  Nitrogen used in the accumulator, off-gassing of construction materials, poor ventilation and sources such as decomposing birds or rodents, can create a hazardous atmosphere.  And if something goes wrong inside a wind turbine, the challenges to rescue are significant.      The National Fire Protection Association is developing a Best Practices Document for confined space entry. This document will address gaps in existing standards and will be more prescriptive in describing things like how to identify potentially toxic atmospheres and select the proper gas monitor for entry and how to include the evaluation of adjacent spaces into your confined space entry program.    This is a document that is looking to go beyond the minimum standards and will provide those looking to develop a “gold star” confined space entry program with the information they need to do so.  Please email me at for further information and/or leave a comment below for discussion.  I look forward to hearing from you!
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