Volume No. 50
Confined Space Entry: Case Studies Provide
The Occupational Safety and Health Administration (OSHA)
defines and requires procedures to ensure safe entry into Permit-Required
Confined Spaces. The following case studies, written by Timothy C. Healey and
excerpted with permission from the May 2007 edition of Professional Safety:
Journal of the American Society of Safety Engineers exhibit safe entry into
By following sound procedures at all times, confined space
tragedies can be avoided. In 2005, inspectors from the Hartford Steam Boiler
Inspection and Insurance Co. (HSB) performed nearly 9,000 confined space
entries. To protect them against related hazards, all HSB inspectors must
complete a rigorous 12-hour initial safety training course plus a 4-hour
refresher course every 2 years. In addition, the company has a robust and mature
safety and health manual that describes its safety standards and provides safe
work practices and/or guidance. It is reviewed and revised annually and
distributed electronically to all covered employees.
Even though more than half of HSB employees are exposed to
significant industrial hazards, the corporate experience modification rate is
0.77 (a rate that is within the BLS statistical business group with the lowest
injury, illness and fatality rates). Despite this enviable record, HSB
continuously strives to be better. The case studies presented here highlight
some lessons learned by the boiler inspection industry.
Industrial Boiler Steam Drum
Scenario: A small industrial facility had two water tube Dtype boilers. One
required an internal inspection while the other remained online. These boilers
are approximately three stories tall with horizontally installed cylindrical
steam drums approximately 15 ft long and 5 ft in diameter with domed/dished
heads and manholes in each head.
The inspector had inspected this brand and type of boiler for
several years, although not at this location. All site personnel were licensed
and appeared to be running the plant well based on the inspector's initial
The boiler had been off-line for 2 days, lockout/tagout had
been applied (per the chief engineer and confirmed by the inspector’s spot
check), and site personnel were observed working in the firebox under the permit
issued the day before that described non-permit conditions.
Activity: The inspector and the chief agreed to start the
internal inspection at the steam drum, which also was covered by the posted
permit. Both entered the space and commenced the inspection After a few minutes
of unremarkable findings, the inspector called for quiet as he proceeded to
check his portable direct-reading atmosphere monitor. He then told the chief to
follow him and exit the drum immediately.
When both were safely outside, the inspector continued to
examine his monitor and determined it was not working properly. The chief
procured another monitor, and a recheck of the atmosphere indicated oxygen
readings near 19.5%. Forced ventilation was set up to vent the space and, after
less than Published by the Connecticut Department of Labor, Project Management Office minutes, it returned to normal levels.
Results: Neither entrant was injured. The inspector realized
his monitor was not working properly after noticing erratic oxygen readings and
no alarm. Subsequent servicing of the monitor found a suspect oxygen sensor. The
inspection continued with a properly working monitor in a normalized atmosphere.
Conclusions: While not a regulatory requirement, constant
monitoring is a good practice even during non-permit -required entries.
Monitoring equipment must be maintained, calibrated and operating properly. In
addition, instrument users must be trained to properly use and care for the
equipment. In this case, a possible low oxygen exposure scenario was avoided
because the entrants followed good procedures.
Scenario: A large trash-burning steam generating facility that generated
electricity was scheduled for an annual internal inspection, as required by
state boiler inspection regulations. Following the site's established practices,
the single boiler plant was shut down and cooled. In making the necessary
arrangements to have the state boiler inspector or his representative conduct
the internal exam, a question was raised about cleaning the ash and other
combustion products off the tubes before the inspection.
Citing a short turn-around time allotted to placing the
boiler back in service, plant management did not intend to do any cleaning
except localized wire-brushing if something needed to be examined in greater
detail. The inspector requested that the firesides be water-washed to remove the
Activity: At the boiler house, the inspector and Point of
Contact (POC) observed two employees inside the furnace. Both employees were
wearing disposable hooded coveralls, filtering facemasks and atmosphere sampling
The inspector questioned why the furnace tubes were covered
with ash. He was told that the furnace had not been water-washed, but that two
employees were standing by to perform wire-brush spot-removal of any ash as
directed by the inspector.
The site’s permit recognized the potential for the presence
of arsenic, silica, lead, cadmium and mercury in the ash residue, as those are
well known to exist as the result of burning trash or garbage. However, no
documents indicated that personnel had checked for such substances. The facility
representative stated that the atmosphere was being sampled via the sampling
pumps worn by the two employees. After the work was complete, the collected
samples would be analyzed for the presence of those materials. The inspector
declined to enter the furnace, deferring to a later time after the furnace had
Results: No entry was made, so there was no likelihood of
exposure to any suspected or known hazards.
Conclusions: This case presented two matters of interest.
First, merely testing the atmosphere at the time of entry to determine the level
of known hazardous materials does not protect any entrants. Mechanical or
abrasive removal of the combustion products will only release more of those
materials into the atmosphere. Site representatives also stated that the entry
personnel were already participating in medical monitoring programs because of
the presence of these heavy metals and toxics.
Second, if the tubes are covered with the ash residue, the
inspector would be unable to inspect the tubes themselves, which is what the
applicable regulations, codes and standards require.
Utility Boiler Steam Drum
Scenario: A large electricity-generating facility maintained a specific large
capacity boiler to operate only during periods of high load. When not online, a
nitrogen blanket was maintained to prevent corrosion.
This utility boiler was six to seven stories tall, with a
horizontally installed cylindrical steam drum 30 ft long and 7 ft in diameter
with domed/dished heads and manholes in each head. The inspector had previously
conducted inspections at this facility, and on this boiler and steam drum. He
was also familiar with the on-site personnel and the site's confined space entry
Activity: The inspector and POC proceeded to the steam drum.
The boiler was coming off lay-up. A manhole was observed to be open, and the POC
tested the atmosphere using a calibrated monitor with 6 ft of hose. He reported
that oxygen was in the proper range and that no flammable gases were detected.
The inspector entered the drum. Once inside, he passed out. The POC, acting as
the attendant/entry supervisor, summoned the site's rescue squad. The squad
arrived on scene in break-out gear and helped extricate the inspector in a
The inspector was administered breathing air by the rescue
squad, which helped him regain consciousness and, thereby, help in his own
rescue. Monitors used by the rescue squad registered oxygen as low as 12% inside
Results: The inspector was taken by ambulance to a local
hospital and released later that day. He had a small contusion on his forehead
and no other detected injuries.
Conclusions: A comprehensive written confined space entry
program was in effect but was not executed properly. Familiarity with the site
and the boiler/drum to an extent caused the participants to make too many
assumptions. These assumptions include the following:
failure to recognize the significance of a (standard)
nitrogen gas blanket or purge having been in place prior to opening the cold
failure to open both ends of the steam drum and force
fresh air ventilation prior to any entry activities;
failure to properly test/assess the internal atmosphere of
the steam drum.
Connecticut Tree Protective Association
and OSHA Renew Alliance
On July 19, 2007, the Alliance between the Connecticut
Department of Labor, Division of Occupational Safety and Health (CONN-OSHA), the
U.S. Department of Labor Occupational Safety and Health Administration (OSHA),
Bridgeport and Hartford Area Offices and the Connecticut Tree Protective
Association, Inc (CTPA) was resigned. This Alliance forms a collaborative
relationship that will help promote safe and healthful working conditions within
CTPA. CTPA members and others will be provided with information, guidance and
access to training resources that will help protect employees’ health and
safety. Special topics include: Procedures followed when working in proximity to
electrical hazards, chainsaw safety, avoiding motor vehicle accidents, proper
job site planning, and safe climbing techniques.
What is a Permit-Required Confined Space?
Confined space entry is not limited to any one specific
industry. From 2003 to 2005, sixty-one workers in America lost their lives to
confined space accidents. Seventeen of these deaths occurred in the construction
So, what is a confined space? 29 CFR 19Published by the Connecticut Department of Labor, Project Management Office.146 provides the
technical answer to that question. A Confined Space is any space that has the
It is large enough or so configured that an employee can
bodily enter and perform assigned work.
It has limited or restricted means for entry or exit.
Is not designed for continuous employee occupancy.
Now the question becomes, is the space a Non-Permit Confined
Space or a Permit-Required Confined Space?
A Non-Permit Confined Space is a confined space that does not
contain, nor has the potential to contain, any hazard capable of causing death
or serious physical harm (with respect to atmospheric hazards). Examples of
nonpermit required confined spaces might include the interiors of HVAC units,
certain air plenums and pipe chases, attics, walk-in freezers or refrigerators,
and some building crawl spaces.
A Permit-Required Confined Space (permit space) is a confined
space that is potentially hazardous. It has one or more of the following
Contains or has a potential to contain a hazardous
Contains a material that has the potential for engulfing an
Has an internal configuration such that an entrant could be
trapped or asphyxiated by inwardly converging walls or by a floor that slopes
downward and tapers to a smaller cross-section; or
Contains any other recognized serious safety or health
hazard. Examples of serious safety or health hazards might include: fall
hazards, unguarded machinery, extreme heat or cold, steam pipes or chemical
lines, hazardous noise levels, electrical hazards, presence of asbestos,
potentially hazardous levels of dust (such as might occur at a Feed Mill).
Permit Spaces have very specific entry requirements which can
be found on the OSHA web site at:
Hazard Corner …
According to the National Institute for
Occupational Safety and Health (NIOSH), more than 60% of confined space
fatalities occur among would-be rescuers. One such incident claimed four lives,
three of which were rescuers.
The tragic incident began when two sewer
workers entered a 50-foot deep underground pumping station via a fixed ladder.
The pumping station measured 8' x 8' x 7' and the metal shaft was three feet in
diameter. The ventilating fan was not functioning and neither worker was wearing
personal protective clothing or equipment.
The two workers were unaware of procedures to
isolate the work area and ensure that the pump had been bypassed. Therefore, the
transfer line was still under pressure when they removed the bolts of an
inspection plate. The force of the wastewater blew the plate off, allowing raw
sewage to flood the chamber and overwhelm one of the workers. The second worker
exited the pumping station and radioed the police department requesting
assistance. He again entered the station and was also overcome.
Two police officers responded to the call and
one officer entered the pumping station. The sewage systems field manager
arrived on the scene and followed the officer into the pumping station. None of
the rescuers returned to the top of the ladder. A construction worker, who was
passing by the site, stopped and entered the station in a rescue attempt. After
descending approximately Published by the Connecticut Department of Labor, Project Management Office feet into the shaft, he called for help. The second
police officer assisted the construction worker out of the shaft. None of the
responding men wore respirators.
Eleven minutes after the incident began, fire
department personnel arrived at the accident and attempted rescue with
self-contained breathing apparatus (SCBA). However, the bulkiness of the
equipment prevented them from accessing the workers. One of the firefighters
became lodged in the shaft, but was unharmed.
No further rescue attempts were made until
professional divers entered the station and removed the bodies. Autopsy results
revealed that the two sewer workers drowned and the police officer and manager
were asphyxiated by “sewer" gas.
This tragedy occurred in 1985. It was
investigated using the Permit-Required Confined Space (PRCS) entry practices in
effect and the following recommendations were made. Current PRCS entry practices
and procedures would have prevented those events.
Recommendation #1: Employers should develop proper work procedures and
should adequately train employees to maintain and repair the sewage system. This
training should include recognition of potential hazards associated with
failures within those systems.
Discussion: The sewer workers did not
have an understanding of the pumping station's design; therefore, mechanical
failures and hazards associated with those failures were not adequately
identified. Records were not kept of mechanical failures or repairs. The sewer
workers 'believed' that a malfunctioning valve had previously been repaired.
This valve permitted the pumping station to flood. The lack of training resulted
in the employee not being able to properly isolate the work area from fumes and
develop comprehensive policies and procedures for confined space entry.
Discussion: Prior to confined space entry, all procedures should be documented.
All types of emergencies and potential hazardous conditions should be addressed.
These procedures should minimally include the following:
Air quality testing to assure adequate
oxygen supply, adequate ventilation, and the absence of all toxic air
Employee and supervisory training in the
selection and usage of respiratory protection;
Development of site-specific working
procedures and emergency access and egress plans;
Emergency rescue training;
Availability, storage, and maintenance of
emergency rescue equipment.
The air quality was not determined before the
sewer workers entered the confined space and the ventilation system was not
functioning properly. One respirator was available for use; however, it was not
appropriate for the chemical contamination (sewer gas) present. Life lines were
not available. Once confined space pre-entry procedures are developed, employees
should be trained to follow them.
Recommendation #3: Firefighters,
police officers, and others responsible for emergency rescue should be trained
for confined space rescue.
A police officer died in
the rescue attempt of the sewer workers. The police officer was not trained in
confined space rescue techniques and did not recognize the hazards associated
with the confined space. The volunteer fireman, who attempted the rescue and
wedged himself inside the shaft, should not have been allowed to enter. His size
alone created a potential hazard for himself and the incident delayed possible
rescue of the victims. Emergency rescue teams must be cognizant of all hazards
associated with confined spaces, including rescue hindrances, and they should
wear proper personal protection and devices for emergency egress.
Adapted from NIOSH’s FACE report #8531. The
full article may be viewed at:
Fatality & Casualty Reporting
State & Town: CONN-OSHA (860) 263-6946 (local) or
Private Employers: Report to Federal OSHA at
Breakfast Roundtable This discussion group will next
meet on September 18th from 8:15 am to 9:45 am. Pre-registration is required.
To be placed on the e-mail distribution list, call John Able at (860) 263-6902
or email firstname.lastname@example.org
OSHA Requirements for Fall Protection and Scaffolding
August 15 from 8:30 – 11:30 This training class will discuss the
OSHA requirements for fall protection and scaffolding on construction sites.
The Control of Hazardous Energy (Lockout/Tagout)
August 23 This workshop covers the requirements in 29 CFR19Published by the Connecticut Department of Labor, Project Management Office.147 The
Control of Hazardous Energy (Lockout/Tagout). This introductory class will take
you through the various required sections of an effective
written lockout/tagout program from beginning to end. If you are new to lockout/tagout
this class will give you the basics you need
to know to get your program running. This class will be held at 38 Wolcott Hill
Road, Wethersfield, CT, from 9-12. For directions
contact Catherine Zinsser at 860-263-6942.
Chemical Hazard Communication September 13 Employees
will be better able to take steps to protect themselves when they
know what the hazards are and how to avoid exposure. This session will help
attendees develop an effective Hazard Communication
OSHA 300 Recordkeeping September 21 At this workshop
you will learn how to fill out the OSHA Log of Work-Related Injuries
and Illnesses (Form 300) accurately and correctly.
Classes are free and held at 200 Folly Brook Boulevard,
Wethersfield, CT in Conference Room A/B from 9 am - 12 noon, unless
otherwise noted in the class description. To register, contact John Able at
(860) 263-6902 or email@example.com.
required. For more training information, visit
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March 01, 2017