Off-site versus on-site application
Applying an intumescent coating system off-site can save time in the construction schedule as it means trades are not required to spend days moving between floors and applying intumescent on site.
After the steel is erected, there is a short period during which applicators are required to be on-site in order to patch any damage caused during installation or to spray steel connections.
General advantages of the off-site application all intumescent coating systems
- Avoids delays in accessing work sites due to construction program delays, continuous inclement weather conditions or other trades occupying floor areas for extended periods of time.
- Reduces the number of trades on-site.
- Removes fire protection application from the critical path of the construction program.
- Improves application productivity as time is not taken up with moving equipment, product and personnel from various areas or floor levels.
- Provides better control of application conditions due to the ability to control environmental conditions such as temperature and humidity, which can prove to be difficult when dealing with open construction sites.
- Allows stricter control of QA processes, leading to a higher quality application.
Specific advantages of the off-site application of Nullifire SC902
- Can be applied directly to blasted steel without the need of a primer, for internal or semi-exposed environments.
- Surface tolerant of light rusting and can be applied up to 2 weeks post blasting, allowing greater flexibility for the painting program.
- Has a 60% faster application and curing time than conventional intumescent coatings, including epoxies, allowing coated steel to be handled and transported the next day.
- Optimises productivity through the paint shop due to high film build capabilities, allowing a single application process to achieve all fire rating levels.
- Quicker delivery of coated steel saves on labour costs and construction delays.
- Very easily sanded for treatment of difficult-to-spray configurations requiring a high level of finish.
Disadvantages of the off-site application intumescent coating systems
- Solvent-based intumescent coatings are not as hard as fully-cured epoxy intumescent coatings, so more care needs to be taken with handling in the paint shop and there are transport loading/securing considerations to avoid excessive damage.
- When coated steel arrives at the construction site, additional care needs to be taken with regards to lifting and erection to avoid damage to the coating.
- Bolted connections need to be dealt with on-site which may cause delays for other trades when these have to be intumescent coated. Intumescent bolt caps can be used, meaning connections are not required to be sprayed on-site. Instead bolt holes are masked during application off-site and, once the steel is erected, bolt caps are attached to either end of bolts to achieve the required fire rating.
Further reading - permax.com.au/using-bolt-caps-for-fire-rating-extrusions
Due to tight construction timelines, access or logistical considerations, it is not always viable to apply intumescent coatings to steel off-site.
In these situations, intumescent applicators will allow for appropriate time and masking of surrounding areas in order to ensure there is minimal disruption to the construction sequence.
Depending on the construction program required the intumescent application can also be broken into stages.
General advantages of the on-site application all intumescent coating systems
- Generally, does not require the use of large or complex spray application equipment, which is very advantageous when dealing with difficult or restricted access on-site.
- All steel work to be intumescent coated is already erected and in place, which significantly reduces the likelihood of damages occurring as can be the case when off-site painted steel is transported to the construction site, off loaded and erected.
- Application of intumescent coating is not a ‘wet trade’ so does not delay construction activities waiting for access to floors.
Specific advantages of the on-site application of Nullifire SC902
- Nullifire SC902 has a low VOC - minimal impact on construction sites.
- Nullifire SC902 is a rapid curing coating and achieves early weather resistance within an hour of application - ideal for open construction sites.
- Nullifire SC902 is very surface-tolerant of high humidity (85% RH) or low temperatures (cures down to 0˚C).
- Nullifire SC902 has an ultra-high film build due to it’s 85% volume solids formulation, which allows the coating to be sprayed in a single application, saving time on-site and delivers speedy access to floors for following trades.
- Nullifire SC902 is easily repaired with minimal surface preparation, using simple application equipment.
Disadvantages of the on-site application intumescent coating systems
- May require specific protection of areas adjacent to structures being sprayed on-site to avoid overspray contamination.
- May not be suitable if installed steelwork does not allow sufficient access to all surfaces that require intumescent spray application.
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