MAINTENANCE AND INSPECTIONS OF FIXED CO2 EXTINGUISHING SYSTEMS
Hello
everyone, we are often asked, "What CO2 level is
dangerous?" CO2 levels above 40,000ppm (4%) are life
threatening. However, there are many other limits placed on carbon dioxide
levels depending on your application.
These limits are defined by agencies such as the Occupational Health and Safety Administration (OSHA) and other regulatory bodies.
Safety guidelines:-
The US a
workplace safety standard is set by OSHA and it defines gas standards, like CO2.
It states that CO2 danger levels begin at 5,000ppm (0.5%) Time
Weighted Average (TWA) for an 8-hour period. This means that the average
concentration cannot exceed 5,000 ppm over an 8 hour work cycle.
Furthermore,
OSHA defines 30,000ppm (3.0%) as it's evacuation threshold. This means
the once the CO2 concentration hits 30,000ppm nobody should be in
the space for more than 15 minutes.
Note that
carbon dioxide is not generally found at hazardous levels unless there is
limited ventilation where gas is being stored or produced, or where the room is
considered a confined or enclosed space.
Additional
compressed gas guidelines for CO2 include but are not limited to:
1. Never
opening a damaged valve
2. Avoiding direct skin contact
with extremely cold liquids or compressed gases escaping from the cylinder
3. Never wear watches, rings, or
bracelets because they can freeze to exposed skin if splashed by an ultracold
gas
4.
Always wear insulated gloves to protect against the cold
At least
every six months, (or more frequently if required by an appropriate authority),
the mechanical parts of the system should be thoroughly inspected and
tested for proper operation by competent personnel. Any electrical
detection systems should be tested quarterly in accordance with the
requirements of BS 5839-1: 2017.
1. Monthly Inspections
1. At
least every 30 days a general visual inspection should
be made of the overall system condition for obvious signs of damage, and should
include verification that:
1.1 all stop valves are in the closed
position;
1.2 all releasing controls are in the proper position and readily accessible
for immediate use;
1.3 all discharge piping and pneumatic tubing is intact and has not been
damaged;
1.4 all high pressure cylinders are in place and properly secured; and
1.5 the alarm devices are in place and do not appear damaged.
In addition, on low pressure systems
the inspections should verify that:
1.6 the pressure gauge is reading in
the normal range;
1.7 the liquid level indicator is reading within the proper level;
1.8 the manually operated storage tank main service valve is secured in the
open position; and
1.9 the vapour supply line valve is secured in the open position.
2. Annual inspections
The
following minimum level of maintenance and inspections should be carried out in
accordance with the system manufacturer’s instructions and safety precautions:
2.1
The
boundaries of the protected space should be visually inspected to confirm that no
modifications have been made to the enclosure that have created un-closeable
openings that would render the system ineffective;
2.4
Check
all control valves for correct manual function and automatic valves
additionally for correct automatic function. Externally examine containers for
signs of damage or unauthorized modification, and for damage to system hoses.
2.5
The
manifold should be inspected to verify that all flexible discharge hoses and
fittings are properly tightened; and
2.6
All
entrance doors to the protected space should close properly and should have
warning signs, which indicate that the space is protected by a fixed carbon
dioxide system and that personnel should evacuate immediately if the alarms
sound. All remote releasing controls should be checked for clear operating
instructions and indication as to the space served.
2.7
Carbon dioxide containers, check weigh or use a liquid level indicator
to verify correct content
of containers. Any showing a loss of more than 10% to be replaced or refilled.
The service life of the cylinders is checked on each visit; every ten years, these are due for Hydrostatic Pressure Testing. When the Hydrostatic Pressure Testing is due, a separate quotation will be issued for this work. The CO2 cylinder hydrostatic test pressure can be anywhere from 3,000 to 10,000 psi. Stored as a liquid at an ambient temperature of 70ºF (21ºC) carbon dioxide has a vapor pressure of approximately 850 psi (5865 kPa). Thus, high pressure cylinders are used for storage, designated as High Pressure CO2.
On each visit to service the electrical detection system, a number of tests and checks, as laid down, are carried out on the control and indicating equipment and the power supply unit output voltage and battery charging rate are measured and recorded.
The system is then tested under mains fail conditions to prove the standby batteries using at least one break glass call point and smoke detector in every zone.
On completion of the test, the battery voltage is measured and recorded, and the system is restored to normal operation.
3. Other minimum recommended maintenance
1. At least biennially (intervals of 2 years ± 3 months) in passenger ships or at each intermediate, periodical or renewal survey in cargo ships, the following maintenance should be carried out.
The
following maintenance should be carried out.
1. All high-pressure
cylinders and pilot cylinders should be weighed or have their contents verified
by other reliable means to confirm that the available charge in each is above
90% of the nominal charge. Cylinders containing less than 90% of the nominal
charge should be refilled.
> The
liquid level of low-pressure storage tanks should be checked to verify that the
required amount of carbon dioxide to protect the largest hazard is available.
The service life of the cylinders is checked on each visit; every ten years, these are due for Hydrostatic Pressure Testing. When the Hydrostatic Pressure Testing is due, a separate quotation will be issued for this work.
On each visit to service the electrical detection system, a number of tests and checks, as laid down, are carried out on the control and indicating equipment and the power supply unit output voltage and battery charging rate are measured and recorded. The system is then tested under mains fail conditions to prove the standby batteries using at least one break glass call point and smoke detector in every zone.
On completion of the test, the battery voltage is measured and recorded, and the system is restored to normal operation.
On the annual visit, the entire system is exhaustively tested.
On completion of any visit, a Service Report and Certificate of Inspection is completed detailing works carried out.
BS
5306-4:2001 further requires that every 12 months a check of
enclosure integrity is carried out. If the measured aggregate area of leakage
has increased from that measured during installation which would adversely
affect system performance, remedial work should be carried out.
The "Authority Having Jurisdiction"
One of the
keys to accurately and effectively monitoring to meet codes is to know
specifically what your jurisdiction requires. This isn't always easy.
Authorities that have jurisdiction over your business can require more
prescriptive codes - but not less.
CO2 Meter recommends you contact your local fire inspector (aka the AHJ) and ask specifically what they require. Inspectors are always open to proactive individuals as it demonstrates your desire to meet their codes and keep your staff and the public safe.
Below Snap
shoot from NFPA 12 2022 Clause 4.8
