FAQ (Frequently Asked Questions)

Our experienced Technical Services Team has compiled a list of FAQ (Frequently Asked Questions) to help you get the information you need.

How can I identify nozzles that are damaged or blocked with Dry Deluge Testing?

Identification of damaged nozzles utilizing dry deluge testing is almost the same as during a wet test. If a nozzle is damaged or partially blocked the spray pattern in a wet testing environment will differ from that of an unblocked nozzle.

Where a normal nozzle has a perfect circular spray pattern, a damaged or partially blocked nozzle will show gaps in this circle. Although with Dry Deluge Testing, the nozzles will demonstrate different spray patterns, the distinction between normal and non-performing nozzles can be easily and efficiently identified.

The pressurised vapor will demonstrate a non-circular vapor cone as well. During a test, you can inspect every nozzle from a close distance of a couple of inches to study the exiting vapor pattern.

This close-up inspection leads to a better identification of the damaged and partially blocked nozzles from the free flowing ones.

Can Dry Deluge Testing save money through time?

Wet deluge tests require a considerable amount of time to prepare. The tests themselves and the clean-up afterwards are very labor intensive. Dry Deluge Testing on the other hand, is far less time consuming.

Preparation and testing are substantially shorter, and the clean-up is minimal because no (sea) water is used during the testing. Complete platforms can be tested in days, rather than weeks. Consequently, Dry Deluge Testing will save money.

How does Dry Deluge Testing prevent corrosion in piping and nozzles?

The patented Dry Deluge Test by SIRON is a method with which to test deluge systems without the use of water. Residual firewater from previous (wet) tests with existing corrosion is displaced from the distribution pipework. Deluge pipework remains dry during testing mitigating corrosion.

After testing, SIRON Deluge Services can additionally coat the inner pipework through the entire deluge system with an environmentally friendly corrosion inhibitor. This “keeping the system as dry as possible for as long as possible” philosophy substantially prevents corrosion build up inside the system.

Is Dry Deluge Testing a guarantee for an uninterrupted production process?

Since Dry Deluge Testing can be arranged to be performed in certain sections of the deluge system, the impact on the operation in the production process is very low and plant can remain live throughout the process.

Furthermore, the Dry Deluge Test negates the requirement for any water ingress protection over sensitive instrumentation and electrical equipment.

No firewater is discharged onto equipment in service, which eliminates the risk of unplanned shutdowns due to water ingress, both during and after the testing.

What do we have to prepare for Dry Deluge Testing?

Preparation for deluge system owners is minimal. SIRON Deluge Services only needs a small space and a power outlet. If required by the scope of work, SIRON brings its own workshop container to the platform.

This workstation is a 10ft. offshore container containing a complete workshop for maintenance and replacement of deluge systems and the Dry Deluge Testing equipment.

Will your vapor trip our smoke or flame detectors?

One of the preparatory steps is to test locally installed flame or smoke detectors by blowing our vapor directly on them. Until now, none of the detectors has tripped while confronted with our vapor.

One of our clients has had independent onshore testing carried out on their own type of Fire and Gas detectors utilizing our Dry Deluge Testing equipment and these tests showed to activation, even when subjected to a very high density of vapor.

Can water mist systems also be tested dry instead of full wet?

Yes, water mist systems can (and often are) tested “dry” in addition to or instead of full wet discharge testing, depending on the stage, purpose, standards, and site conditions.

Water mist systems are a specialized form of water-based fire suppression that produce very fine droplets. Like traditional sprinkler systems, they can use various configurations (wet pipe, dry pipe, pre-action, deluge/open-nozzle). Testing practices align with relevant standards such as NFPA 750, EN 14972, FM approvals, or industry-specific guidelines (e.g., marine/offshore).

Common Dry Testing Approaches

• Flow and nozzle pattern testing with vapor: Specialized “dry deluge” or vapor-based methods use pressurized air, or vapor (instead of water) to verify flow paths, check for blockages, confirm nozzle discharge patterns/orientation, and detect obstructions. This is particularly useful for open-nozzle/deluge-type water mist systems. (NFPA 25 & FM Global 2-81)

Why Use Dry Testing?

• Reduces corrosion and damage: Repeated full wet tests (especially with seawater in offshore/marine settings) can cause scaling, microbiologically influenced corrosion (MIC), salt buildup, and nozzle blockages. Dry methods minimize this.
• Safer and less disruptive: Avoids water damage to equipment, electronics, or sensitive areas; reduces downtime and environmental impact (e.g., no large wastewater volumes).
• Allows more frequent checks: Dry tests can supplement mandatory periodic wet tests, improving overall reliability between full discharges.
• Commissioning and maintenance: Hydrostatic (wet) pressure tests and full flow discharges are still required for final acceptance and certain intervals, but dry tests handle initial verification, ongoing inspections, and performance of pumps/valves/nozzles.

Can dry deluge testing be a solution to reduce Corrosion Under Insulation (CUI)?

Yes, Dry Deluge Testing can help reduce the risk of Corrosion Under Insulation (CUI), but mainly by minimizing unnecessary water exposure during fire protection system testing.

Here’s the key idea:

• Traditional wet testing of deluge systems introduces water into piping, nozzles, supports, and nearby insulated equipment.
• Any trapped moisture that remains under insulation can accelerate CUI, especially on carbon steel operating in the typical CUI temperature range (roughly 0–175°C).
• Dry testing methods verify valve actuation, release logic, alarms, and control functionality without fully flooding the system.

That means dry testing can:

• Reduce repeated wetting cycles around insulated assets
• Lower the chance of moisture ingress into damaged insulation or jacketing
• Reduce standing water in low points and supports
• Decrease maintenance-induced CUI initiation

However, it is not a complete CUI solution on its own.
CUI is usually driven by a combination of:

• Water ingress
• Poor insulation sealing
• Damaged cladding/jacketing
• Chlorides or contaminants
• Temperature cycling
• Inadequate drainage
• Coating degradation

So dry deluge testing is best viewed as one layer in a broader CUI mitigation strategy.

• Yes, dry deluge testing can materially reduce one contributor to CUI: unnecessary moisture exposure.