Airless spraying for fire protection – Graco Mark X

We were on the construction site with a customer and a Graco Mark X ProContractor to carry out fire protection work using Hempel Hempafire Pro 400. Using this example, we’ve summarised the most important information about fire protection spraying in this blog post. Let’s start with the question of why fire protection coatings should be applied with an airless device. We also provide an overview of equipment selection, commissioning and cleaning the airless machine after spraying.

Airless coating of steel beams with fire protection (flame retardant)

Why use airless spraying for fire-resistant coatings?

To increase the strength of structural steel sections or beams in the event of a fire in a building, an insulating layer is applied after appropriate pre-treatment. At temperatures of 500°C, the load-bearing capacity of steel components decreases after just a few minutes. In this case, the foamed insulating layer has a cooling and insulating effect and protects the steel from critical temperatures for a certain period of time (e.g. 90 or 120 minutes).

To ensure this, a high layer thickness must generally be applied. As a general rule, the thinner the component, the thicker the insulating layer needs to be. If you want to work particularly economically, you can’t do without a suitable airless paint sprayer.

Thanks to the airless process, the fire-resistant coating is applied evenly and to a high quality. The result of the fire protection work is very similar to conventional steel painting. In the case of our customer, this involved steel beams that had to remain visible after coating. Especially in cases where a certain appearance is required, it becomes important to spray the material with the right pressure and nozzle.

Which paint sprayer is right for fire protection?

Following detailed advice from our team, the customer opted for a Graco Mark X ProContractor. We also adapted the accessories to suit the customer’s projects. The main product used today for the application is the Hempel Hempafire Pro 400.

That’s why we fitted the airless with a PAA321 nozzle. We also had a PAA319 nozzle on site, just in case. The 319 nozzle delivers slightly less and therefore prevents the application of too much fire-fighting product, particularly during the first few attempts at spraying. This makes spraying easier for the first user, who doesn’t need to react as quickly. Once the routine is established, the PAA321 nozzle is then used.

Here is a selection of airless equipment suitable for projects involving fire-resistant paints:

• Graco Mark V ProContractor
• Graco Mark VII ProContractor
• Wagner HC 750 E
• Wagner HC 950 E
• Graco Mark X ProContractor

Commissioning the machine with Hempel Hempafire Pro 400

First, the unit was thoroughly rinsed with Hempel Tool Cleaner 99610 to ensure that all residual materials from previous use were completely removed from the system. The unit’s main filter was removed and the Graco Blue Texspray gun (without filter) was installed. The Hempel Hempafire Pro 400 was then vacuumed and the pressure adjusted.

According to the manufacturer, the material is sprayed at a pressure of over 200 bar with airless nozzles measuring a size of 0.017″ – 0.023″ inches. In the first spray test, we were able to obtain a usable spray pattern at 160 bar. In this case, the pressure should NOT be increased unnecessarily, as this could also increase the formation of spray mist.

What is the best way to clean the airless device afterwards?

An important point: When cleaning solvent-based products, use the cleaner recommended by the manufacturer, as this is directly adapted to the material in question. When changing the materials to be sprayed, it is important to always pre-rinse the machine with the correct dilution for the material being used, to avoid any problems caused by incompatibilities. If these particularities are taken into account, cleaning can be carried out as in this video.

 

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For any further questions or if you would like to get your hands on one of these products seen in this article, you can contact us on +49 (0) 30 220 15436, fill out our contact form or email us. If you wish to purchase one of the products mentioned above, you can check them out in our online store. You can also visit us at our service base during office hours.