Feature 1 | PAINTS, SEALANTS & COATINGS All in the mix


A critical factor in the effectiveness of passive fire protection (PFP) coatings is that they are applied ‘on ratio’. Fluid handling solutions company Graco has introduced the Graco XM PFP plural-component sprayer, featuring greater system control, productivity and data reporting


structures such as oil and gas platforms and vessels. Applied to steel, these coatings work by increasing in volume and density in reaction to intense heat exposure (for example, from hydrocarbon and cellulosic fires). Tis effectively insulates the steel structure, protecting it by delaying heat transfer, therefore extending the time before structural failure occurs and buying valuable time to bring the fire under control and/or evacuate personnel. However, to ensure the fire protection


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properties of a plural-component coating, it is critical that it is applied correctly to the specifications outlined by the coatings manufacturer; there is no margin for error. As Graco spokesman Stephan Rindfleisch explains: “Applying material with the wrong mixing ratio can change the properties and reduce the time in which the substrate or structure can withstand a fire exposure.” Epoxy intumescent PFP


coating


components can be hand-mixed, but this is very labour intensive and limits the amount of square meters that can be coated per day. Rindfleisch explains that an electronic proportioner, or plural component sprayer, mixes on demand, which means that only the amount of material needed will be mixed when the system’s airless gun is triggered. With the whole mixing process automated, the process is less labour intensive; there is less waste; and subsequently less flushing is required to clean the system between jobs. Te Graco XM sprayer is engineered to


handle two-part material ratios from 1:1 to 10:1 and offers a raſt of features that include: live ratio assurance; USB data reporting; adjustable ratio; and the addition of new temperature controls and heating system. “Prior to the release of the Graco XM


PFP machine, ratio assurance could only be achieved by breaking from spraying


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The control screen allows the user to monitor ratio readings in real time


and conducting manual ratio checks,” says Rindfleisch. “Typically this happens four or five times a shiſt…up to and over an hour of any eight-hour shiſt can be lost performing ration checks.” As an electronic proportioner, once set up, the Graco XM PFP sprayer continuously monitors the material mix ratio. Te system has a +/-5% ratio tolerance level, and in the event that the system registers ‘off-ratio’ conditions, the system alarms and shuts down production before the mix can reach the spray gun.


poxy intumescent coatings are often used to provide passive fire protection (PFP) to offshore


An adjustable ratio removes the need for costly changeovers between jobs with different specifications


The required component ratios are


entered via an easy-to-use control panel with two display and operation modes: ‘set up’ and ‘run’. Graco has simplified the ratio checking process so that it can readily be performed in the press of a few buttons. Te ratio check process is initiated using the machine controls and the operator then dispenses materials A and B into test beakers and weighs them. Once the operator has entered the weights of A and B on the control screen, the screen will then display a pass or fail message which is automatically logged. Te sprayer, which offers real-time data


readings, tracks and records data in relation to ratio mixes, pressure, temperature, flow rates and material usage, and offers data reporting to verify that the coating has been correctly applied. Te reports for the job can be downloaded via a USB port. The system’s heating controls enable


a consistent temperature level to be maintained. Rindfleisch tells Offshore Marine Technology: “A minimum temperature is required to be able to spray, and…there is a maximum temperature as the materials will start to change properties when exposed to a too high temperature. Terefore a good temperature conditioning and monitoring system is required to maintain the optimal temperature.” The sprayer is capable of applying


material at around 12litres/minute, but Rindfleisch notes that a typical application will never use this high flow rate, as “a typical flow rate is between 4 and 6litres/ minute”. One unit can be used to handle a job size ranging from 50m² to 50,000m², although, for large-scale projects, multiple units would likely be used to complete the work in a reasonable time frame. OMT


Offshore Marine Technology 1st Quarter 2013


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