Dry Deluge Testing- Reducing costs whilst improving safety and enhancing operational efficiency
Regular testing method
Normally deluge systems, water spray systems, open water-mist systems, foam systems and compressed-air-foam systems require yearly mandatory function testing. Since these open extinguishing systems are the primary means of protection in the case of a fire, function testing is a mandatory requirement for personnel, equipment and environmental reasons. They are typically annually tested with brackish or seawater. During these wet function tests unforeseen complications within the system pipework, as well as risks to personnel during the complete process.
- -Spray of sea water over an entire platform is a hazard for the expensive and critical processing equipment and many platform activities will be disrupted while testing,
- -Wet testing causes growth of MIC (Microbiologically Influenced Corrosion), corrosion built up and salt crystallization to the flow pipes and nozzles,
- -Excessive firewater discharge will overflow the sump / drain tanks,
- -Freezing of firewater can be quite dangerous to operators in Arctic conditions,
- -Risk of unplanned business loss and plant shutdown due to water ingress,
- -Exacerbation of any existing corrosion within carbon steel systems.
Understandably traditional wet deluge testing is a very time-consuming process and therefore a costly maintenance routine due to preparations and operation.
New Development
The patented SIRON Dry Deluge Test eliminates many of the regular problems. It uses a pressurised water-based vapour instead of sea water. Any flow problem in pipes and nozzles will be detected quickly and can be carried out in an uncomplicated and cost reducing way within the HSE / NORSOK / NFPA guidelines. Whilst not a complete replacement for wet deluge testing, the use of SIRON Dry Deluge Testing can potentially extend the periods between wet testing to 5 years or more.
Case Study
The 110v/240v vapour generation unit heats up an integral element to heat the test fluid which then produces a water-based vapour. A 2” hose is connected immediately downstream of the deluge valve via a check valve on the deluge system that is to be tested. Once at temperature the unit fan is initiated allowing the water-based vapour to migrate downstream of the deluge system ultimately exiting the deluge nozzles. Whilst migrating downstream any corrosion or particulate within the system is quickly identified by erroneous spray patterns coming from the nozzles. Any anomalies found re-investigated by using a portable borescope camera. Damaged nozzles can be quickly identified also due to erroneous spray patterns of the water vapour during the test. Damaged nozzles are one of the most common failure modes on any fire protection system and can affect the density application rates or in worse cases can affect the overall hydraulic balance of the deluge system.
Key Benefits of Dry Deluge Testing
- -No marine growth, new corrosion or salt crystallization will form in deluge pipework and nozzles after testing with pressurized vapour,
- -The complete system is live throughout the process and the equipment does not impede the flow path of firewater to protected areas,
- -Damaged, blocked and partially blocked nozzles are quickly identified as well as ruptures or damage to pipework,
- -No complicated electronics are used, and the DDT equipment has a small footprint,
- -Dry Deluge Testing does not rely on the system being clean or having up-to-date hydraulic calculations and isometric drawings,
- -Testing deluge systems dry brings a more scientific approach to all previously available inspection based dry testing routines,
- -Dry Deluge Testing has been extensively field proven on and offshore and is regularly used in Dutch, Danish and UK offshore sectors and also UK nuclear power plants.
Dry Deluge Testing reduces costs because
- -It is efficient and has no disruption to normal platform activities,
- -Preparation time for Dry Deluge Testing is considerably shorter,
- -Smaller teams required means less bed space is required resulting in cost saving to client,
- -Typical time for single Dry Deluge Test and borescope inspection is less than one work shift,
- -Complete platforms can be tested in days rather than weeks.
Dry Deluge Testing is safer because
- -No water ingress protection is required to be installed over sensitive instrumentation orelectrical equipment,
- -Pipe wall failures are easier to identify,
- -Deluge pipework remains dry mitigating corrosion,
- -Residual firewater from previous wet tests is displaced from the distribution pipe work,
- -No freezing of firewater in water traps throughout the deluge system or on platform decks,
- -Reduction in corrosion to surrounding plant and protected areas and general infrastructure.
Application
Since the introduction in 2010 Dry Deluge Testing has been conducted on deluge systems
throughout Northwestern Europe. Examples are:
Scope
Dry Deluge Testing is a very simple, cost-effective operation. Two operators can do the complete test in a few days. Exact timing will depend on the scale of the deluge system, but typically a single deluge system can be tested in less than one shift regardless of the size. All equipment needed, can be shipped on a pallet and has a small footprint. If testing is combined
with maintenance of the deluge system or expansion of the existing system, a 10ft. container will be shipped to the site.
Patent
Ever since the initial inventing and optimization Dry Deluge Testing SIRON sought for a means to protect this innovative procedure both as intellectual property as well as the methodology and operation. Patenting of Dry Deluge Testing proved to be the most effective protective measure for the intellectual property and as such SIRON now hold a Global Patent for the technology.
Guidelines
The patent SIRON Dry Deluge Testing holds, is conforming to the HSE Section 10.2.1.4 and allows other maintenance intervals to be set dependant on the results of visual inspection and operational tests. (Health and Safety Laboratory RR1046 Research Report)
Dry Deluge Testing is also in line with the NORSOK Standards; if intervals for full-scale testing of facilities in seawater-resistant materials give two independent successful results, the interval can be increased to a maximum of six years. (Norwegian Oil and Gas recommended guidelines #075 for water based firefighting systems)
Dry Deluge Testing is also according to the following NFPA Standards.
NFPA 25 Paragraph 11.3.2.3
Where discharge from the system discharge devices would create a hazardous condition or conflict with local requirements, an approved alternate method to achieve full flow conditions shall be permitted. (Full Flow Test to be achieved through a Test Header and tests shall be conducted to ensure that the foam-water system(s) responds as designed, both automatically and manually.)
When tested wet or alternative method nozzles should always be checked on:
NFPA 25 Paragraph 11.3.2.6.1
The discharge patterns from all of the open spray devices shall be observed to ensure that patterns are not impeded by;
-Plugged discharge devices and to ensure that
-Discharge devices are correctly positioned and that
-Obstructions do not prevent discharge patterns from
covering surfaces to be protected.NFPA 25 Paragraph 11.3.2.6.2
Where obstructions occur, the piping and discharge devices shall be cleaned, and the system retested.
Attested by bureau veritas
The patented SIRON Dry Deluge Test has been given an attestation by Bureau Veritas:
Cert. No. 15ABD11103 Rev. 0
In the Clearwater attestation Bureau Veritas writes:
The SIRON 240v Vapour Generation Unit is fit for purpose and if operated as per QA 021 Rev 01 –
Performance Standard for dry testing of deluge systems with the use of the SIRON 240v Vapour
Generation Unit.
The Bureau Veritas inspection report 15ABD11049 Rev A also allows the use of the SIRON 110v
Vapour Generation Unit as long as the unit is operated as per QA 021 Rev 01.
Correct use of the SIRON Vapour Generation Unit will identify the following deluge Failure Modes:
References:
Author- Mr. Avnish Sharma, Vice President, SHM Shipcare SE Asia
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