DEP Jurisdiction
and Registration of Sources
The exposure of persons
to radiation from radiofrequency (RF) and microwave heaters,
sealers, and industrial ovens is regulated in New Jersey under
N.J.A.C. 7:28-42 "Radio
Frequency Radiation", and is administered through N.J.A.C.
7:28-48 "Fees for the Registration of Nonionizing
Radiation Producing Sources." Owners of any of the sources
described below must register these devices with the Department
30 days after taking possession of these sources on a registration
form provided by the Department. There is a registration
fee, based on the number of sources at a facility and the
frequency of the radiation utilized by the source. The amount
of the fee is listed in Subchapter 48 and is assessed after
the registration form is received and processed by the Department.
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Background Information
on Radiofrequency Heat Sealers
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Radiofrequency
heaters and sealers may operate between the frequencies
of 300 kilohertz and 299 Megahertz (MHz), although
the most commonly used frequency for this type of
device is 27.12 MHz. These devices are also known
as RF heat sealers, solders, fusers, molders, fasteners
or embossers; high frequency sealers or dryers; and
electronic or electromagnetic sealers or welders.
Heat sealers emit high energy radiofrequency radiation
between two conductive plates. These plates are part
of a press which, when closed, will clamp two or more
pieces of non-conductive material such as vinyl or
plastic together. When the plates are energized, the
material is fused. The conductive plates are dies
(forms) which conform to the shape of the area to
be sealed. Objects of various shapes may be sealed
by changing the dies to fit the material. Specific
uses of RF heaters and sealers include the manufacture
of many plastic products such as toys, vinyl loose-leaf
binders, tarps, awnings, life-jackets, various plastic
and vinyl medical equipment, rain apparel and packaging
material; wood lamination and veneer processes; embossing
and drying operations in the textile, paper, plastic
and leather industries; and the curing of various
materials, including plasticized polyvinyl chloride,
wood resins, polyurethane foam, concrete binder materials,
rubber tires and epoxy resins. The advantages to utilizing
sealers of this type are that the seal is very strong
and complete, and that solvents are not required.
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According to the Food
and Drug Administration's Center for Devices and Radiological
Health, heat sealers may expose their operators to radiation
fields 10 - 100 times higher than the radiation limits specified
in N.J.A.C. 7:28-42, Radio Frequency Radiation. The National
Institute for Occupational Health and Safety has reported
that in certain cases, workers' hands have been exposed to
radiation levels greater that 8,000 times the limits specified
in Subchapter 42.
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Background Information
on Microwave Heaters, Sealers and Industrial Ovens
This category includes
sources which operate between the frequencies of 300 MHz and
100 Gigahertz. Some of these sources are used to process and
prepare food. Others are used to dry, cure, sanitize, disinfect,
and change the chemical composition of wood and dyes. Some
of these sources are used in applications similar to those
of RF heat sealers, and they may also be used in industrial
and academic research. Microwave disinfection units are now
being used by hospitals to treat medical waste.
These sources, as a
group, are less likely than RF heat sealers to expose workers
to radiation levels in excess of the limits specified in Subchapter
42 because of the way that electromagnetic waves interact
with human body tissue at higher (microwave) frequencies.
Nevertheless, many microwave sources may be out of compliance
with Subchapter 42 and their operators may work in close proximity
to these sources for eight hours a day. Therefore, the Department
requires all microwave heaters, sealers and industrial ovens
not specifically exempted to be registered with the Department.
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Exemptions
Exempt from the registration
requirements are; all unaltered microwave ovens used strictly
to cook food for consumption, which may include, but is not
limited to, microwave ovens in restaurants, canteens, cafeterias,
and other eating establishments; and microwave ovens purchased
by consumers for use in the home. Also exempt from registration
are unaltered microwave ovens designed for consumer use, but
purchased by a business for uses other than the cooking of
food, such as the drying of laboratory samples.
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"Miscellaneous"
Category
The following devices
must be registered: nuclear magnetic resonance units (non-medical),
inductively coupled plasma units and plasma etchers. The registration
categories into which they fall is determined by the frequency
of the radiation used.
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Radiation Exposure
Limits
Radiofrequency and
microwave heaters, sealers and industrial ovens must not expose
their operators, any other worker at their facility or any
member of the general public to radiofrequency radiation levels
in excess of Subchapter 42's limits. The Department estimates
that 2 out of every 3 heat sealers is out of compliance. Absorption
of high levels of radiation from these heat sealers may cause
fetal abnormalities, infertility, low sperm count, damage
to eyes and hands, and cancer promotion.
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Reducing Radiation
Fields from Heat Sealers
As with any system
that generates high levels of electromagnetic energy, there
are potential safety problems associated with their operation.
When designed and operated properly, these devices should
not produce high levels of radiofrequency radiation in the
vicinity of the operator. However, if the shields designed
to protect the operator from overexposure are not properly
installed, are not made of the proper materials or completely
absent, then the levels of radiofrequency radiation to which
the operator and other neighboring personnel may be exposed
can be many orders of magnitude higher than Subchapter 42's
exposure limits. The intensity of the radiofrequency radiation
field to which the operator may be exposed can also be influenced
by the proximity of the heat sealer to other RF sources, the
proximity and composition of all stationary and non-stationary
objects near the source and the proximity of the operator
to the source. If shielding is needed and it is not possible
to retrofit the heat sealer with shields, it may be possible
to reduce operator expose to a safe level by having the operator
stand in a different location when the heat sealer is utilizing
radiofrequency radiation or by reducing the on-time of the
radiofrequency radiation over a six minute time period.
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