Where is FM Global headed?

Editor's note: The following article represents the author's opinions, which are not necessarily those of Professional Roofing or NRCA.

Those of you who have read my past dissertations regarding the changes at FM Global and its efforts to approve virtually all elements of the construction industry, such as through FM Standard 4490—Roofing Contractors, know I generally have been open-minded about roofing contractor approval and supportive of Factory Mutual (FM) Research in its pro-active efforts to promote and build better roof systems.

But after FM Research's presentation at NRCA's 115th Annual Convention and Exhibit, it is much less clear just where FM Global wants to be relative to the roofing industry. The presentation raised many more questions than it answered.

The latest idea

What FM Research has referred to in the past as "Navigator" gradually is becoming reality and was introduced and hyped to the roofing contracting community as RoofNav—a virtually infallible, foolproof way to specify and construct FM Research-Approved roof systems. It was touted as being a computer program that eliminates all ambiguities in roof system specification and literally interprets billions of combinations of materials to come up with an FM Research-Approved roof system for every application.

In the strict binary sense, computers do not make errors, but those of us who have struggled through the many software programs available know very well that software programs are not infallible and without innumerable errors. Does FM Global really think it will be the first in history to develop an infallible, absolutely user-friendly software program?

Perhaps if someone is designing a roof system for a new facility, RoofNav will provide valid information about Approved roof systems. The major problem will be that FM Research-Approved roof systems may not always be the most technically correct solutions or commonly commercially available.

Remember, Approved roof systems are those that someone has paid FM Research to test and approve. There always are ways to construct a roof system to give it a better chance to pass the tests that don't necessarily get included in commercially available roof systems' and assemblies' specifications.

For instance, if a supplier wants to pass a wind-uplift test with a wide sheet membrane roof system, he uses a Type E steel roof deck for the test assembly. Type E steel roof decks provide better fastener-withdrawal resistance because of the type of steel alloy. The problem is that Type E steel roof decks are not commonly installed, and most general contractors, deck installers and roofing contractors (including myself) could not recognize a Type E roof deck if their lives depended on it.

I seriously doubt FM Global engineers responsible for overseeing installations of Approved roof assemblies would visibly recognize a Type E steel roof deck is different from a common carbon-steel roof deck and required for a given roof assembly much less differentiate among the types of roof decks in the field. And finding a Type E roof deck on an existing facility may be the challenge of one's career.

The only FM Research criterion for a Class 1 steel roof deck assembly is that a steel roof deck be FM Research-Approved; no mention is made of a specific type of roof deck except in the proprietary report provided to the party who paid for the test (which does not typically become public information).

Practicalities

So can a typical finished roof assembly installed under typical field conditions meet the criteria for an FM Research-Approved assembly when "special" components (those not typically installed or included in manufacturers' specifications) are not included in a roof assembly? The installed roof assembly may only resemble the "tested" roof assembly. But sooner or later, lawyers will define differences among steel roof decks after a failure if a project is large enough and there is enough money in it for them.

Or consider that stainless-steel insulation fasteners are FM Research-Approved components for a roof system. The only criteria imposed by FM Research with regard to insulation fasteners is that they survive a prescribed time in the Kesternich Chamber without showing signs of red rust. Stainless steel never will show red rust and is commonly believed to be corrosion-proof. Stainless steel resists corrosion and will pass the Kesternich Chamber test hands down.

But stainless steel and carbon steel (used in roof decks) are about as far apart as they can be on a metals nobility table. The larger the nobility table spread, the faster the less noble metal will be degraded by electrolysis in the presence of an electrolyte (such as water).

So when roof insulation becomes wet around stainless-steel fasteners driven through a carbon-steel roof deck, the electrolyte is provided for galvanic reaction and the carbon-steel roof deck quickly degrades around the fastener. When the steel breaks down around the fastener, withdrawal resistance becomes nil, but the stainless-steel fastener has survived; however, it is unable to perform its intended function—to secure roof system components.

Nobody wants to pay FM Research to conduct deck-corrosion tests, nor is there any indication FM Research has considered such testing. The problem is that FM Research already has taken money from somebody to test and approve stainless-steel fasteners; is FM Research now going to recommend against their use in Approved roof assemblies? And will all the Approved combinations of various types of roof insulation and insulation fasteners vanish into oblivion when RoofNav only lists Approved roof assemblies?

Base-ply fasteners for lightweight insulating concrete roof decks always have been nebulously referenced in FM Research literature, specifically FM Global Property Loss Prevention Data Sheet 1-29, "Above Deck Roof Components."

FM Research never has differentiated between base-ply fasteners with 1-inch- (25-mm-) diameter heads and fasteners with 3-inch- (76-mm-) diameter 1-90 discs (or, for that matter, between base-ply fasteners and large-head roofing nails). Common sense prevails in recognizing that a base ply secured with 1-90 discs will not require as many fasteners for a given wind-uplift classification as a base ply secured using 1-inch- (25-mm-) diameter heads.

But remember, someone must pay for testing at FM Research, and there is no incentive for a fastener manufacturer to pay FM Research to determine that fewer fasteners are required for wind-uplift classifications—after all, they are selling fasteners. And when calculating the fastener density for base plies by FM Research criteria, the quantity of fasteners with 1-90 discs is the same as that for a fastener with a 1-inch (25-mm) head.

When FM Research's recommended perimeter/corner enhancement criteria are applied, a roof membrane is virtually bonded to the surface of 1-90 discs and the deck literally is pulverized by fasteners installed so closely on center. It is difficult to believe a pulverized roof deck will provide acceptable uplift resistance though the density of the fasteners is as prescribed. But because nobody pays to test a pulverized roof deck, no one knows just what the uplift properties may be.

RoofNav problems

According to present FM Research criteria (Data Sheet 1-29), fastener pull-out testing and calculations for fastener density based on average pull-out resistance of a roof deck are recommended. Will RoofNav allow the consideration of similar criteria or differentiate between base-ply fasteners with 1-inch- (25-mm-) diameter heads and fasteners with 1-90 discs when providing an infallible definition of an "Approved" roof system? Time will tell, but it seems unlikely that with our present understanding of RoofNav, there will be any room for differentiation among fasteners or evaluation of an existing roof deck's condition.

If FM Global's RoofNav program is to provide technically correct solutions to roof system specification and installation, it will be necessary for FM Research to conduct some "nonrevenue" testing because simply listing Approved roof systems in its RoofNav solutions may not provide the world with better performing roof systems.

It would almost appear that there can be no Approved reroof/re-cover roof systems under the inflexible conditions imposed by computer software and the previously recognized "Accepted" category of roof systems will cease to exist. So what solution will RoofNav provide for roof system replacement and re-cover options?

Consider the fact that between 60 percent to 70 percent of roofing projects involve reroofing or re-covering. Roof assembly variables expand exponentially in the roof replacement arena, and FM Global acknowledged billions of combinations now become multiple billions (we will all have to invest in mainframes to handle the electronic overload). So far, there has been no indication by FM Research that RoofNav is or will be interactive, which means RoofNav output will be prescriptive without providing for input by the user about the many variables encountered in a typical reroofing project.

Here's an example: Let's say you have a roof system replacement project over an existing steel roof deck for an FM Global-insured building (I'll make it easy in that you might get some help from FM Global if the project is for one of its insureds). The specification requires an FM Research-Approved Class 1 roof assembly. The criteria for a Class 1 roof assembly are that all components be FM Research-Approved—individually and as an assembly. Was or is the existing steel roof deck approved by FM Research? Any idea how you could tell? Even if the original specifications are available, there is no assurance that the specified materials actually were installed. Can you provide a Class 1 roof assembly without this information?

The current recommendation for joist spacing for FM Research-Approved steel roof deck assemblies for Class 1 construction is a maximum 5'-6" (1.7 m); the existing joist spacing is 6'-6" (2 m). Will RoofNav make a judgment call allowing a new FM Research-Approved Class 1 roof assembly to be installed over the existing noncompliant structural system even though the joist spacing exceeds current recommendations to allow you to comply with the requirement for the specified Class 1 roof assembly?

If you are lucky, you may get an FM Global engineer to decide the existing conditions will be acceptable and the insured's roof classification will not be affected by the deviation. But if FM Global engineers rely solely on RoofNav for their decisions, reroofing will become mighty interesting when FM Research criteria are applied.

Now, take the same scenario in the case of a non-FM Global-insured building requiring an FM Research-Approved Class 1 roof assembly. (The building owner subscribes to the RoofNav package and has decided FM Global recommendations are in his best interest.) Good luck! You can be sure FM Global engineers will not return your telephone call or initiate any correspondence to make such judgment calls for noninsureds, and the owner may be unreasonable enough not to pay for the roof assembly if all questions are not resolved in writing before commencing work.

And if you are trying to retrofit an existing metal roof system, you may not live long enough to even get acceptance (if that option still is available) by an FM Global engineer.

Consider the effects on current roof system replacement practices given the fact that manufacturers/brokers/suppliers of roof systems pay for testing and approval of their proprietary roof systems; approved assemblies are most prescriptive in the components included in a tested assembly; and any deviation from a tested assembly will result in a rejection of the roof assembly by FM Global engineers (with the assistance of RoofNav) as being noncompliant with an Approved assembly.

Given a concrete roof deck, saturated roof insulation, and removal and replacement of an existing roof system, many roofing contractors choose to remove wet materials, allow a roof deck to dry as much as possible and install a temporary roof membrane to keep the roof deck watertight until a new roof system can be expediently installed. If the temporary roof membrane was not included in the tested (Approved) roof assembly, it is unlikely RoofNav will accept the roof system as "Approved" unless the temporary roof membrane is completely removed from the concrete roof deck.

And if the roof deck and temporary roof membrane are to be covered with a sloped-to-drain cellular concrete fill without the temporary roof membrane, the chances for water entering the interior during installation of the cellular concrete fill become highly likely.

Will FM Global assume responsibility for interior damage? Not likely. Will the temporary roof membrane affect the performance of the roof assembly? Highly unlikely, but RoofNav will not make that call considering the program's relative apparent inflexibility.

And the same principle applies to vapor retarders. Most tests conducted for roof system approval do not include vapor retarders; how will RoofNav evaluate the inclusion of a vapor retarder in a new or retrofit roof system? Virtually all FM Research-Approved vapor retarders are not vapor retarders at all but laminated kraft paper sheets intended to be installed over steel roof decks that have passed the wind-uplift and fire-resistance qualities prescribed by FM Research.

RoofNav may not recognize the inclusion of a vapor retarder in a roof system. If blanket acceptance of a vapor retarder is included in RoofNav, there could be RoofNav-approved roof systems over concrete or cementitious wood fiber roof decks, including kraft paper vapor retarders—not a particularly technically correct application.

Perish the thought of trying to include a multi-ply bituminous vapor retarder in a RoofNav-approved roof system. There certainly is no incentive for vapor retarder manufacturers to pay FM Research to test their products with all the available approved roof systems. It might get interesting!

In short, RoofNav is being touted as "the last word" in roof system specifications—an infallible software package that will not allow the specification (and, theoretically, installation) of a roof system that is not FM Research-Approved. RoofNav is to be the ultimate guide for FM Global engineers to ensure Approved roof systems are installed. Unfortunately, without some basic roofing knowledge, FM Global engineers remain at a disadvantage in understanding even the basic terminology of roof systems to be included in RoofNav.

What it means for you

Given the variables that currently do not appear to be accounted for in RoofNav, this gets to be a truly scary scenario for roofing contractors. In some instances, it will not be possible to construct a technically correct roof system and comply with contract bid documents, or, inversely, RoofNav inadvertently may cause more problems than it corrects in some applications. And if FM Global engineers become solely dependent on information provided by RoofNav and elect to make no judgment calls about existing roof assembly conditions, life will become difficult.

In 2000, NRCA's Technical Operations Committee spent a great deal of time and money to develop a useful format for the FM Global Approval Guide with the blessing of FM Research. This year, the new FM Global Approval Guide remains the most unusable, least understandable and incomprehensible document ever created since the time of stone tablets. But there is hope. Contractors are led to believe the recommended format is being incorporated into RoofNav. Now, the main question is whether FM Research can muster the talent necessary to fill in the blanks in the new format to provide understandable, useful information for RoofNav users.

And speaking of talent, the interpreters of FM Research recommendations are members of the FM Engineering Group, a separate entity within the FM Global system.

My experience with FM Global engineers is that they are competent, conscientious engineers performing a difficult function with an overwhelming workload. The problem is they do not know anything about roof systems and have no real way to learn about the various types of roof systems about which they are expected to make judgment calls every day.

Unfortunately, the current FM Research information referencing roof systems is incomprehensible even to those who have a good understanding of roof systems and FM Global criteria much less an engineer who may not know the difference between surfacing aggregate and surfacing granules. And this gets back to RoofNav, the answer to FM Global engineers' dilemma regarding judgment calls.

A recent experience drove home the complications arising from a relatively small project for an FM Global insured. The job was about 60 squares (540 m²) and was completed in just under two weeks. Submittals for the aggregate-surfaced built-up roof (BUR) membrane system were submitted to FM Global engineers through the general contractor in early November.

On Jan. 4 of the following year (after the project had been completed for more than one month), the general contractor received communication from FM Global noting that "the perimeter area would need additional fastening but is not recommended for this building needing an FM 1-60 roof if you proceed with the proposed FM 1-90 roof … ."

The specifications called for an FM 1-90 roof assembly and perimeter enhancement for the roof deck, and the roof system components were included as the roof assembly was constructed. The submittal referenced an aggregate-surfaced BUR membrane system that was listed in the FM Global Approval Guide. An appendix was enclosed with the FM Global engineer's communication that described a two-ply BUR membrane with a modified asphalt cap sheet as being the "closest" Approval Guide specification to the submittal and a notation that "… we cannot accept your proposal at this time."

Following additional correspondence with the FM Global engineer calling attention to criteria for "Acceptable" roof system construction defined in Property Loss Prevention Data Sheet 1-29, a "senior" review engineer provided a "one-time only" acceptance with the strong implication not to submit a nonapproved roof assembly construction for the next project.

Virtually all FM Research acceptable variations to Approved roof system constructions are found in Property Loss Prevention Data Sheets, which essentially supplement the Approval Guide. Will RoofNav include the variables now contained in current Property Loss Prevention Data Sheets? Is the long-time "Accepted" roof system vanishing with RoofNav? Will FM Global engineers be able to access acceptable variations of an Approved roof system and exercise some judgment in assessing existing roof assembly conditions? Some roofing education of FM Global engineers will be required. Time will tell, but at the present time, don't get your hopes up.

The subscription cost to RoofNav currently is either undetermined (or undisclosed) by FM Global. If the cost to subscribe to RoofNav is relative to the cost for one Property Loss Prevention Data Sheet (currently $75), the only people likely using RoofNav will be FM Global personnel.

Closing thoughts

FM Global is conveying the idea that it wants to be everything to everybody but will provide no support to anyone who is not an FM Global insured. The program's implementers (FM Global engineers) are limited by heavy workloads and basic lack of roofing knowledge, and the organization is plagued with high personnel turnover. Even with RoofNav online, evaluations and Acceptance of submitted roof systems may be a long time coming. Submit information to FM engineers early, and do not get caught with a completed project that is formally rejected by FM Global engineers after the fact.

Maybe FM Global sees RoofNav as a way to entice everyone to become FM Global insured—no premiums paid, no support for better ideas. I simply cannot assess the motivation for selling this program to the roofing community without provision for personnel to support the concept unless the package is envisioned as a "cash cow" for a supposedly nonprofit organization.

In time, all things become evident. With any luck, it won't take long for the motivation for this program to become apparent. But it appears contractors should be most wary about jumping into what could prove to be a relatively untenable situation created by an insurance carrier dictating roofing policy depending on "paid-for" testing without evaluating the systems touted as being Approved for technical accuracy. Remember Uncle Remus' tar baby; you may not be able to extricate yourself from the tar.

RoofNav may prove to be infallible in providing approved roof system solutions, but it will not necessarily provide technically correct solutions unless FM Research begins to evaluate the technical and real-world properties of Approved roof systems. Approved roof systems are not necessarily better performing roof systems (except maybe for fire and wind resistance, but there are other considerations). I now believe there may be better alternatives—not necessarily including FM Global's vision of grandeur.

Dick Baxter is president of CRS Inc., Monroe, N.C.