General Reference:
OSHA Personnel Protection Standards relating to high temperature
surfaces.
OSHA does consider exposed heated surfaces, if
there is a potential for injury, to be a hazard and will issue citations if
employees can come into contact with such surfaces. While there are not any
OSHA standards, except those that are applicable only to specific industries,
which address exposed heated surfaces, there are several OSHA general
standards, which address such hazards. Those standards are:
1910.261(k)(11):
Steam and hot-water pipes. All
exposed steam and hot-water pipes within 7 feet of the floor or working
platform or within 15 inches measured horizontally from stairways, ramps, or
fixed ladders shall be covered with an insulating material, or guarded in such
manner as to prevent contact.
1910.262(c)(9):
Steam pipes. All pipes carrying steam or
hot water for process or servicing machinery, when exposed to contact and
located within seven feet of the floor or working platform shall be covered
with a heat-insulating material, or otherwise properly guarded.
1910.23(c)(3):
Regardless of height, open-sided floors, walkways,
platforms, or runaways above or adjacent to dangerous equipment, pickling or
galvanizing tanks, de-greasing units, and similar hazards shall be guarded with
a standard railing and toe board.
1910.147: The control of hazardous
energy (lockout/tagout) standard covers hazardous energy, including thermal,
during the servicing and maintenance of machines or equipment. Thermal energy
may be dissipated or controlled, and it is the result of mechanical work,
radiation, or electrical resistance. This standard addresses practices and
procedures that are necessary to disable machinery or equipment and to prevent
the release of potentially hazardous energy while maintenance and servicing
activities are performed.
1910.132(a):
Protective equipment, including personal
protective equipment for eyes, face, head, and extremities, protective
clothing, respiratory devices, and protective shields and barriers, shall be
provided, used, and maintained in a sanitary and reliable condition wherever it
is necessary by reason of hazards of processes or environment, chemical
hazards, radiological hazards, or mechanical irritants encountered in a manner
capable of causing injury or impairment in the function of any part of the body
through absorption, inhalation or physical contact.
The personal protective equipment standard would
apply to hot surfaces where the hazards have not been eliminated through
engineering or administrative controls. This standard requires employers to
assess the workplace to determine if hazards that require the use of PPE are
present or is likely to be present. The employer must select and have affected
employees use properly fitted PPE suitable for protection against these
hazards, as well as provide employee training and conduct periodic inspections
to assure procedures are being followed. Suitable thermal protection would be
necessary to provide employees with thermal insulation from hazardous hot pipe
surfaces.
Section 5(a)(1) of the OSHAct:
Each employer shall furnish to each of his
employees employment and a place of employment that are free from recognized
hazards that are causing or are likely to cause death or serious physical harm
to his employees.
The private sector has specifically addressed the
issue of exposed heated surfaces. The national consensus standard,
"Standard Guide for Heated System Conditions that Produce Contact Burn
Injuries (C 1055-92)," issued by the American Society for Testing
Materials (ASTM)1
addresses this issue. The standard establishes a means by which the engineer,
designer, or operator can determine the acceptable surface temperature of an
existing system where skin contact may be made with a heated surface. Personal
injury resulting from contact with heated surfaces can be prevented by proper
design of insulation systems or the usage of other protective measures. A copy
of that standard has been enclosed for your information.
Also, ANSI A13.1-1975, "Scheme for the
Identification of Piping Systems," issued by the American Society of
Mechanical Engineers2, is
enclosed. This standard specifies the identification of the contents of piping
systems on the basis of legends and color to warn personnel of outstanding
hazards inherent in the materials involved.
Finally, enclosed is an article, "Preventing
Burns from Insulated Pipes."3 It
answers the question: "What is an acceptable temperature to ensure that no
skin burn will occur if a surface is touched?" The article is based on
guidelines given by the National Insulation Manufacturers Association (NIMA)
and gives the amount of insulation needed to ensure that the acceptable
temperature is not exceeded.
1 "Standard Guide for
Heated System Surface Conditions that Produce Contact Burn Injuries (C
1055-92)." American Society for Testing and Materials, Philadelphia, PA.
2 Scheme for the Identification
of Piping Systems, ANSI A13.1-1975, American National Standards Institute. New
York, NY: American Society of Mechanical Engineers.
3 "Preventing Burns from
Insulated Pipes," Chemical Engineering, Vol. 88, No. 15 (July 27, 1981),
pp. 58-64.
The PRIMER...In a boiler steam bubbles are continually bursting at the steam water interface and ejecting boiler water drops into the steam space.
As the water level is raised the volume of the steam space is decreased, the speed of the steam across the surface is increased drawing foam and water droplets towards the steam outlet. A sudden increase in steam demand can cause a slug of boiler water to enter the steam outlet. This is known as priming. Operation of the boiler below its design pressure will also produce a similar effect.
