PIPE DREAMS –
Vacuum Systems: From the Pump to the Patient
Fred
Evans, CEO
Medical Gas Management, LLC
Vacuum
or suction, as it is sometimes called, is considered a vital life support
therapy and treatment. Types of suction vary from oral tracheal to
remove mucus and secretion, chest drainage to remove fluid, and surgical
procedures to remove irrigation liquids, blood and related debris.
Vacuum systems are dry by design. They consist of the SOURCE of
supply (vacuum pumps) distribution piping, terminal inlets and alarms.
Fluids suctioned from a patient are collected in canisters. The level,
or amount of suction, is required to be regulated depending on the volume
and viscosity of the liquid being suctioned.
Collected fluids are considered contaminated and caution should
be used in handling all vacuum equipment from the pump to the patient.
The flow of air, or vacuum, is also considered contaminated. Whether
your job is plumbing, mechanical, biomedical engineering or nursing,
general isolation procedures should be followed. Rubber gloves, face and
eye protection, and protection of exposed clothing is recommended. To
prevent the spread of infection and disease, personnel charged with the
responsibility of servicing inlets, alarms or pumps should have tools
dedicated to the service of vacuum system components.
Normal vacuum systems produce depth of negative pressure between
19 and 25 IN Hg. The other important measurement in a vacuum system is
“flow”. Flow is a measurement of volume expressed in
“standard cubic feet per minute” (SCFM).
The minimum NFPA Standard of flow is 3.0 SCFM or .85 Liters Per
Minute (LPM) at the inlet. The size of pipe or internal diameter is the
most critical factor in assuring adequate performance. This theory is
best demonstrated by trying to drink a Wendy’s Frosty through a
standard straw. Remember, the larger the straw, the easier it is to move
the liquid.
Vacuum pumps are sized for peak-calculated demand. In the real
world vacuum regulators are left in the “on” position. This
not only puts a load on the pump, it sucks dust and debris into the
regulator, vacuum inlet and system. Over time, debris builds up reducing
the inside diameter of piping and tubing. Testing the system components
may show deep vacuum but loss of performance because of the
restriction.
The most common issues of low suction and the solution are
identified here:
Dirty Vacuum Inlets– Disassemble, clean or clean with vacuum
cleaning solution (VSC 2000).
Dirty Vacuum Regulator– Disassemble and clean or clean with
vacuum cleaning solution (VSC 2000).
Incorrect Connection of Vacuum Regulator to Inlet– Vacuum
Regulator and collection canister should be supported by vacuum slide,
not inlet.
Incorrect Tubing– Use thick wall, large diameter tubing to
prevent kinks to connect all components.
Leaking Canister– Insure proper connection and fit.
Liquid and Solid debris– Use overflow safety trap bottle
between canister and vacuum regulator.
Test and document flow of all vacuum inlets and remember flow
lower than 3.0 SCFM can be increased and corrected. Consult a vacuum
system specialist at 1 (800) 732-9035 and remember “My Vacuum System
Sucks” is a good thing.
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Education Can Make the Difference
Tom
Evans, VP
Medical Gas Management, LLC
Recently, MGM provided a
medical gas system Plan and Specification Review for a customer, a
service we regularly provide at a reasonable cost. A copy of the
project’s written specification and a blueprint bearing the
appropriate seal from the engineering firm and the State Department of
Health were e-mailed to us.
The project’s written spec was scrutinized for compliancy to
current NFPA, AWS, ASME, CGA standards and local and state statutes. The
author’s lack of experience in medical gas system design and
installation was recognized immediately. References made to
“applicable standards” included “NFPA 56F”
Nonflammable Medical Gas Systems”, an obsolete standard replaced by
NFPA 99 in 1987. Other standards cited were either obsolete or
non-applicable plumbing specifications with no correlation to medical gas
systems.
The “Installation” section of the specification, made
no mention of installer qualifications or installer testing of the
assembled system. Installation included the use of “argon or carbon
dioxide” for purging the pipes while brazing. Current NPFA
standards do not allow these gases. Only oil-free, dry nitrogen may be
used for this purpose
The “Commissioning of the System” section of the spec
consisted of one paragraph requiring that “The system (note lack of
reference to various gases) must be tested for safety and be acceptable
prior to project completion.” This statement is far too broad to
assure code compliance and patient safety.
The drawings provided for the project referenced NFPA 99 that did
not match the references to NPFA 56F in the written spec. The result
— installer confusion. A tie-in to an existing system was
indicated, however, the original piping had been relocated and no longer
existed in the area shown. Obviously, the project engineer had not
visited the job site to survey current conditions, relying instead on the
facility’s original construction print dating back 15 years.
Numerous crossed lines involving oxygen and nitrous oxide were
identified. This potentially life threatening condition could have been
missed due to the vague nature of testing required under the Installation
and Commissioning sections of the written specification.
Numerous plan notes contained the instruction “to be
determined” leaving the installer faced with decisions of
significant design importance, user compatibility and system function.
Remember, this is the same installer who, by project specification, was
not required to have any qualifications.
True to form, the plans also showed improper placement of zone
shut-off valves (inside the rooms they serve), lack of required alarms in
ICU and Post Anesthesia Recovery areas, and too many alarms in Surgery, a
waste of valuable labor and material dollars providing no benefit to the
customer. Additionally, a full piping run of approximately 160 ft.
traversed the vaulted ceiling space above the hospital’s main lobby,
not particularly a code violation but certainly aesthetically
undesirable.
Cost to correct these design discrepancies were estimated to cost
$180,000 had they not been identified in our review prior to
installation.
The NFPA 99 medical gas documents take exception to design
characteristics of non-flammable medical gas systems. They fortunately
do require, in Chapter 4, that qualified individuals having experience in
such installation install the systems. Prudently, they also require
specific testing of these systems to verify, by certification, that all
provisions of the document are adhered to and that the system’s
integrity be maintained or achieved. We should expect architects and
engineers who play such a vital role in the construction process to have
the appropriate training and necessary experience to produce design
documents that will direct the construction in specific elements of
materials, assembly and testing.
Required qualifications of the installer are currently limited to
experience and a demonstrated ability to braze a copper-to-copper pipe
joint. Except in a few states, no specific training, testing or
education is required. What about the certification process? Again no
particular training, experience or education is required.
Except for the efforts of organizations such as Piping
Industry/Progress and Education, (P.I.P.E.), Medical Gas Professionals
in Healthcare Organization, (MGPHO), American Society of Sanitary
Engineers, (ASSE), National Inspection, Testing and Certification, (NITC)
and Medical Gas Management, LLC, little has been accomplished in setting
qualification standards for those who perform critical functions in the
medical gas system construction process.
There can be no compromise when it comes to patient safety. As
professionals who have responsibility for the systems we design, install,
service or test, we must increase our levels of competency through
education, training, and staying current with changes in standards and
code requirements. We believe our patients expect it, but more
importantly we believe they deserve it.
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