Improve your HVAC system, Reduce the Installation Time

Dec 01, 2020 by Carlo Luisi, Marine Technical Manager- Europe

2020 will be remembered, unfortunately, for the Covid-19 Pandemic, that impacted the entire world.

Like most markets, the shipping industry was heavily affected by the pandemic, with thousands of ships stopped, for long periods, and with new mandatory safety regulations for sailing .

One of the latest focuses to come from the pandemic are ways to improve the HVAC system, such as increasing the numbers of air changing and cleanings during the day, to reduce the circulation of the virus.

To be in compliance with the new requirements, the air conditioning units need to be modified and powered, and as a consequence, many air distribution lines need to be increased in size and in numbers.

By chance, STI Marine Firestop has recently developed a new solution that allows spiro lines to pass through decks and bulkheads, without the need for welding.

As “is” solution Vs. STI Marine Firestop “smart system”

The current fire protection solution for the air distribution line passages, known as “Spiro pipes or ducts”, is to use slightly larger steel sleeves (according to the Spiro line’s cross sectional area) that can vary from 200mm in length to 900mm in length.

This solution requires that the Spiro lines be adapted to the steel sleeves using a transition junction and accessories.


Particularly for new  construction, the installation of the Spiro lines starts from the steel sleeve, once it has been continuously welded on both sides of the division.

This means that, if not well coordinated, the installation of the steel sleeves and the availability of the shipyard to do the work can cause a bottle neck, which will slow down the installation of the spiro lines.

The STI system has been developed to create a faster and independent way to install fire protection for the HVAC spiro line penetrations.

The biggest benefit of the system is that it allows for the Spiro lines to pass through the division continuously, without any interruption. In this way the Spiro lines can be installed without waiting for the steel sleeves to be installed and welded.

Another big advantage is that the system eliminates the hot work activities, since the need for steel sleeves has been eliminated.

Furthermore, either pre-insulated and uninsulated spiro lines can be used with the STI system, reducing confusion and avoiding the possibly for installation errors.

Additionally, the Firestop collar and insulation can be installed quickly and easily, giving flexibility to the entire installation of the HVAC lines.

The STI Marine Firestop  system is simple and only consists of:

  • Pre insulated Spiro Pipe/Duct
  • MFC collars
  • MFS Marine Firestop Sealant and MFB530F Marine Filler Blanket with Foil

The MFC collar can be attached to the division with the use stich welds or screws. A small bead of MFS sealant needs to be applied between the collar and the Spiro line, as a smoke seal.

Then foil faced blanket is applied at the end of installation as shown below.

Bulkhead and deck installation Mock-up at Norway shipyard

Installing the STI Marine Firestop system has a number of advantages:

  • Run Spiro Lines Continuously – Reduces the number of Spiro sections and coupling accessories
  • Spiro line installations may be done without the need for welded steel sleeves to the division eliminating staging conflicts
  • Reduces and/or eliminates welding on board
  • Increases the flexibility of the HVAC spiro pipes installation
  • Reduces the installation time.