Yup, about a 50:1 expansion for the 'thin' coatings and about 5:1 for the 'thick' coatings. Also it tends to sag when multiple coats are needed to obtain higher fire ratings.

what does it mean to sag? I haven't noticed this before in our projects. You mean it hangs off the steel, or it has uneven thickness and pools in the center of beams? I'm very curious what I've missed right in front of me.

yeah, i don't get this comment. i imagine that in a controlled and properly applied, this product won't "sag".

Is this what you mean by sagging? (source)

That's exactly what I mean by sag.  In my limited experience it tends to occur when using solvent based 'thick' products where you have to apply multiple layers to get a higher fire rating (90 min plus). The paint itself is heavy and thick, combined with a high viscosity and it sags to some degree regardless of conditions and application.   Never had an issue with the 'thin' products.  

That looks like shit. If I recall higher rated assemblies need to be applied over a long period of time, and one reason to do it in a factory controlled setting. Plus, I mean, gravity?

The sagging is usually an issue of applying a coat too thick. I think this is mainly an issue with the one-component formulations (water- or solvent-based). The outermost portion of the coat dries faster than the underlying portion and the skin that develops can look wrinkled or sagged when the underlying portion that is still liquid moves because ... well, gravity as b3ta puts it. 

Thinner coats are able to dry more evenly and sagging shouldn't be as much of an issue. But thinner coats means more coats (more labor, more money, more time) because these coatings need to build up a certain DFT over the steel in order to protect it from fire. I've been told that you can sand the surface of the coating down to get rid of the sagging, but you can only get so far with this, it requires adding/buying extra material so you can sand away some of it, and more labor/money/time. 

Even though they are called thin-film coatings, they can get pretty thick depending on the steel member it is protecting and the hourly rating required as Chad pointed out. I think they are also usually field-applied in the one-component formulations. I've been looking for more information on this but not really finding anything definitive, but I have had conversations about this with product reps. 

There are two-component epoxy intumescent coatings that are more readily able to be shop-applied because they set faster, and are harder films so they are better able to resist damage during transport and erection. These two-component ones are also able to be applied in thicker films per coat reducing the number of coats required (less labor and less time ... like a day or two rather than weeks).

Also note there should be a distinction made between what I'm calling intumescent coatings and what I will call intumescent paint. The coatings are actually fire-resistive coatings with hourly ratings having been tested to ASTM E119. The paints are fire-retardant coatings usually only with flame-spread classifications according to ASTM E84. The fire-resistive coatings are meant to protect structural members to achieve a certain fire protection rating (e.g. 2-hours), but the fire-retardant coatings are meant to be applied to combustible materials to achieve a certain flame spread classification (e.g. Class A, or B). The application that Client describes above would be an example of an intumescent paint, probably to ensure that the lumber was a certain flame-spread index (though I don't know about it being a powder that could be mixed into other paints).

Thanks for all of the info EA! That was very informative.

You're applying int-paint to a gypsum board surface? Never heard of that before. Got a UL design no. to share?

The Engineering Judgement is in the mail!

https://shieldindustries.com/fireguard_wp/fireguard/fireguard-e-84/

The Floor/Ceiling assembly data sheets are presented as remediation to existing construction (i.e. before/after).

The FC9 assembly w/ engineered wood joists and a gyp soffit does seem to offer a "UL 263 Small Scale Test" designation.

I don't think the presentation on the data sheets precludes using it in a non-remediation application (i.e. new construction). UL 263 is just a test comparable to ASTM E119. The IBC allows both for determining fire-resistance ratings of building elements. 

I haven't dug deep into it, but it does seem like a code-acceptable method of achieving an hourly rating in the assemblies shown on their website. 

Still seems weird that the painter can't figure out how to estimate the job though.

What you're suggesting is not an allowable fire-protection solution where I practice. This sounds ridiculous.

You're the painter, and you can't figure out how to price a job. Sounds like you're out of your element on this one and you should let the GC hire someone who knows what they're doing.

We've done it here for repairs multiple times. Basically, the original construction used Type X on the ceiling... Type C is always the ceiling UL assembly. Note to archs; "Type X" has become a generic term used in code and the usg manuals, but if you crack open the reference UL assembly, only Type C is approved. Another note; you can't add insulation if it isn't listed or you need to add another layer of gyp. So, take a apartment building, 5 stories, 5 buildings. You can't tear out the gyp without moving out. You can't add a layer without resetting every fixture and sprinkler head; and moving everyone out. But intumescent paint solves that... it goes on like paint... The product by itself has the test certifications and installation requirements.

Interesting point there Mighty. I'm the only one in our office that writes Firecode C for 13mm gypsum board... even though my building code still refers to type X. 

 Anyways, back to the spray product, I'm aware that there are various testing options south of my border... but reading the tech sheet EI linked to in an above post, the manufacturer claims the product is "formulated to meet test standards"... and it does not appear to actually be formally listed under any UL tested assemblies or standards. This seems sketchy to me.

Does the code north of the border require that an assembly be listed with ULC? Or does it require that the assembly determine its fire resistance rating per the Canadian equivalents to ASTM E119 or UL 263?

Yes to your second question... but it's more complicated than that. We have ULC S101-17 (fire endurance test) and ULC S102 (surface burning) which will determine if a product can be considered non-combustible (for use in non-comb req construction). 

 Fire-ratting, at least in ontario (the most restrictive of provincial building codes) is either by ULC (or ULc) design no. or by material additive method (OBC SB2). The later does not have an option for intumescent paint to gypsum (or any IT paint I believe).

If a product is tested under S101 and S102, then it will be listed on the UL website accordingly and its acceptable assemblies will be searchable.  From my 5min of searching the archives, I find no-mention of this product, or the parent company, in any directory which leads me to believe that this product (fireguard E84) is not acceptable up here.

BTW, Type C is not always required for the rating in a ceiling/floor assembly (here is a generic example from the GA directory). Rather than indicate Type X or Type C on the drawings. I reference the tested design by the UL designation (or other). The specs have both types and the contractor will need to use whichever product matches the tested assembly (some have multiple options ... for example, check out all the acceptable options for gypsum board in the UL design matching the GA listing I linked to earlier). Without some compelling reason, if both a Type X and a Type C product are acceptable in the tested assembly, I don't care which one the contractor uses.

NS that's interesting. You stated that, "If a product is tested under S101 and S102, then it will be listed on the UL website accordingly and it's acceptable assemblies will be searchable." 

I don't think that's the case in the States. Any accredited testing agency can test to the UL test and write a report stating the rating achieved. That alone should be sufficient for code compliance. I don't think there is any requirement to report that testing to UL for inclusion in the directory (with I'm assuming an associated cost).

^ You're probably right... our hands are tied up here in regards to S101 and S102 (and a few others) so we often have to reject alternatives because of lack of official paper-trail.

It still doesn't mean that a code official doesn't think listing in the UL directory is required. I've run into a few of those on projects before. Some can be reasoned with, some can't. Same goes for code officials that require ICC-ES reports.

Official testing under ULC S101 and ULC S102 are required here. That's the first stop but there are other tests required based on the material and use. All of these are listed in the front-end of the code.  We simply cannot accept, at face-value, products with alternative testing agencies.

There is some room for negotiations but we've been unsuccessful 100% of the time so far... and we've tried. There is a "get out of jail free" clause in our code that allows the AHJ to request a judgement letter when in doubt. These can only be provided by a fire-protection engineer, which we are not. It is rarely worth the trouble to go this route since normally this is a result from a GC submitting an alternative and asking us to justify if it's an acceptable substitution. In that case, I ask the GC to seek, and pay for, the letter. That normally ends the discussion.

@Everyday Arch... good point, sometimes Type X is fine, but the vast majority of those use solid sawn lumber and older assemblies. Others might be two layers of Type X.

This looks to be in the realm of what OP was referencing, based on a loose interpretation of commercial below, residential above:

Are there only ULC labs that can conduct that testing? Or could an independent lab become accredited to perform ULC testing without having to go through the ULC organization? The Guardian Lab that tested the E-84 product shows accreditation for testing to ULC S101. Are you saying the Canadian code wouldn't allow Guardian to test the assembly and certify its compliance with the S101 testing requirement? 

P.s.: Not trying to pick a fight or be aggressive about this. I'm just curious. You've got the experience in dealing with this up there. It just seems odd to me.

EI, you've done more research on this than I have today, but the doc you link would imply that the product has passed the required testing. This would make this particular product acceptable for use in FRR assemblies (with some education to the AHJ required) however, there are very few non-ulc design solutions that use intumescent paint (acceptable in my code). Our code limits us in how we can use products to achieve fire-ratings and IP is not an option available for walls/floors when establishing a rating by additive measures. If backed into a corner, I could see a way to argue for this but it is a tough fight.

Just checked. There is nothing specific in my code regarding IP but the language of the "determining fire-rating" section is pretty clear: A product can be used as long as a product has a fire-rating tested under S101. So with that in mind, it could be argued that a IP could be used to achieve a desired FRR to a gypsum board surface in my area without having the product tested (and listed) by UL if a 3rd party has equal test results. Convincing the AHJ is another story. TIL. Neat.

Cheers. I learned something new today too. Can't say I'm going to start using this everywhere, but in situations like mightyaa described earlier ... it's good to know it could be an option.

Throwback to: Architects learn new things everyday.

agreed, just don't think I'd ever consider IP to gypsum board unless it's in an inaccessible space or really high. Love the throwback link.

Interesting. NS and I are both in Canada. Just today I was trying to figure out a fire separation issue where a steel beam runs directly along the top of a concrete wall. Neither need structural fire protection. Figured the only way is to spray with IP or similar to get the separation we need. And I'm still not even sure that's the right answer.

I have not applied intumescent coatings myself but from what I've seen it's pretty comparable to latex paint. You would want an airless gun to spray it, not HVLP. I believe I've heard that it lays down in 10-mil increments but that's stretching my memory, and it would be manufacturer-dependent.

Your question is a bit ridiculous for this forum, which is for design professionals to trade war stories. Are you in any online construction or finishes groups? They would be better oriented to advise you. 

To add to WG and EI's comments above, I've honestly never seen IP applied in a way I would deemed visually acceptable. The trades always rush to get the req thickness in the least amount of passes and that shit dries up with so many streaks... So we stopped using it on exposed steel. All this to say that if you budget your application labour like typical paint, you'll probably get a bad final product and run the risk of a redo. So try to account for extra time to get the finished look right and free of streaks.

Isnt there an issue with Int. Paint sagging? I would be worried about the application process of a ceiling.

^That was my point. The finish never looks good.

You can always spend the money on factory applied intumescent if it's that critical, but all of the applications I've seen on high profile projects seem to be satisfactory. Perhaps better prep and people that actually know how to spray will help.

FWIW, 30 mils DFT isn't that bad for an intumescent. It could be done in two coats of the product in question. Three if you were concerned about the finish sagging. You could also roll it on per the data sheet ... although at a thinner WFT per coat so it would take more overall labor to achieve the same 30 mils DFT.