MBIE Guidance for Alternative Solutions

Hi All
MBIE have just published Guidelines in regard to how Alternative Solutions are to be addressed. Apart from the fact that they have rubber stamped the C/VM2 process, and that safety factors are now required to be stated, they have quite mistakenly quoted clause C 5.5 as requiring “adequate provision of water must be made for fire fighting operations”. In fact, C 5.5 states “Buildings must be provided with the means to deliver water for fire fighting to all parts of the building”. This has nothing to do with the provision of water, it is solely to do with providing the reticulation for others to supply water to.
If you go down this path, every industrial site in the country will end up with a 2000m3 reservoir, on the off chance that a fire breaks out. Are MBIE going to pay the $200K+ for each of these tanks?
The second item of concern is the statement that C/VM2 has built in safety factors. Having asked MBIE on multiple occasions what the safety factors are, and how they have been calculated, I have yet to receive any response. I suggest that MBIE probably do not know what the actual safety factors are.
Comments please.
Paul C

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The MBIE Guidance for alternative solutions is completely worthless as there are a lot of words that do not say anything meaningful or useful.

Doubling down on the FEB is stupid as the process does not suit minor departures from the Acceptable Solutions. It looks like the time and effort that was put into the working group was thrown away in favour of this guidance.

In relation to safety factors if you take the base time to initiate evacuation of 30 s from the FEDG (an assumption) then multiply it by x 1 through to x 60 you get the results in C/VM2 Table 3.3. There is no explanation or justifications for the times listed in the table, but MBIE are satisfied with multiplying by 1 in certain situations.

As you’ve pointed out the description of C5.5 is misleading and it suggests that they have written that list without understanding what they are writing or referring to. It is quite concerning.


C/VM2 has negative safety factors in some cases. For example, the travel speed through smoke is unaffected by visibility, when in fact it drops of quickly once it is less than 10m or so - see Jin’s research in the SFPE handbook where it drops down to 1/4 of the C/VM2 speed. With a sprinkled building, visibility is not a criteria, even if you have 999 people.
This has 2 effects - RSET is much longer than calculated, and the CO takeup for FED(CO) is higher than calculated as people are exposed for longer.
There is no especial allowance for occupant variation such as age or ability. The same FED limit is used for children, or old age pensioners in their non fire separated retirement apartments as for fit students. Fit young students were the basis for the research on CO uptake for the FED theory. How well does this fit the population group?
These simplifications do however make the calculations easier…
The safety factor in C/VM2 is otherwise 1 or close to it. Many of the values are those which you would take from the literature or common practice - visibility = 10m, FED=0.3, travel speed is slightly derated from the theoretical maximum of a standard adult flow rates are as per the SFPE handbook, soot yields are from Wade and Robbin’s paper on furniture fires, the fast fire growth for non storage fires matches Young’s research where (as I recall) 95th percentile furniture fires are “fast”.

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Is the “unfortunate typo” part of the general push for FFFC implementation and placing responsibility for infrastructure of the town mains onto the fire engineer by any chance? I wish who ever writes this stuff was both accurate and clear…

Hi All, This one is now coming up on the FEB reply from FENZ. It is clearly in the wrong place as the FFFC is NOT part of the documentation needed for Buidlign Code compliance and is NOT a Buidlign Consent item. I have written to Simon to see if this can be corrected.


  1. Building Consent Items
    The following items are considered to be detailed design elements that are considered to be required as part of the consent stage documentation. They have been identified at this stage to avoid delays during consenting.
    2.1. 27-07-2018 - Fire-fighting Facilities and Access Arrangements
    Please ensure that all requirements for the FFFC with Jon Rewi are agreed and stamped prior to submittal of Building Consent documentation. Matters that need to be resolved are agreement on:
    a. The location of the attendance point,
    b. Any additional handstands and entry points to facilitate the required less than 75m maximum hose run distance to reach all areas within the building noting that a hydrant system will be required in any case due to the height of the proposed drying tower.
    c. Adequacy of proximate water supply to address the fire risk as detailed in NZS4509:2008
    d. Location of fire alarm panel and any mimics as required
    e. Any security arrangements (security gates, perimeter fencing, etc.) that may restrict prompt access to site.
    f. Procedures of any processing machinery that may be required to remain in operation,
    g. Location of all Hazardous Substances and/or Flammable gases and the shut-off valves for their safe isolation. Evidence of the FENZ agreement to any proposals should be provided at Consent.

Hi Alan,

Apart from 2.1c. which is dealt with at resource consent stage, why would you want to hold of resolving these issues till the construction stage when there are limited options and time to do anything meaningful?



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I have no issue with it as recommendation, but it can not be forced, a bit like FEB (voluntary), construction monitoring (Council), co ordination statements (architect role) PS4 (not legally enforceable and carries huge liability) etc…Does the fire engineer now take liability for water in the main as well? I don’t think so given that there are so many variables that can affect the calculations.

As you asked me an open question here is one for you:

Why would you, and SFPE, not support the legally required position, and therefore the membership, and stop accepting and supporting unnecessary risk and liability. What is happening is that we are being more and more commercially affecting as smaller practices and also commercially disadvantaged as CPEng over the “fire designers” who have none of these requirements pushed onto them?



Hi all

Having been involved in the Alternative Solution working group before the MBIE Fire Programme ran out of steam I have a few comments on this recent release - some just my thoughts as I reviewed the document, and some in response to the comments made above.

  • There were a number of actions the working group recommended, and most were around various guidance documents that we considered were required to support Alternative Solution design. This included for example, guidance on the FEB (which SFPE are now looking into), guidance for BCA’s on review of alternative solutions (not progressed), some advice on what types of experience or qualification would be required to undertake or review alternative solution design - depending on what type of alternative solution it was, some guidance around common NZBC terminology (not progressed), and some guidance on Factors of Safety, etc.

  • The very first document we strongly recommended MBIE release was some simple re-messaging around the fact that alternative solutions were indeed an acceptable method of demonstrating compliance with the NZBC and that alternative solutions could include the likes of deviations from compliance documents so long as they were documented and justified appropriately.

  • The document MBIE have released is essentially this initial re-messaging (that’s my take anyway). The Working Group authored an initial draft guide that looked quite similar to this. It had a bit more information on for example, expertise and experience requirements for doing and reviewing alternative designs, a few more examples of various types of alternative solutions, and a bit more information on the FEB process. MBIE (at the time) condensed this down quite a bit and drafted a shortened revised document. The information on the FEB for example was considered better placed in some separate guidance, and some of the examples were removed to make the document more concise. The document released last week looks very similar to the reduced draft I saw early last year - with a few modifications (the table describing the various Code clauses for example)

  • So I don’t think this guidance replaces all the hard work the Working Group did on the Alternative Solutions project, it is simply the actioning of the first (and perhaps most important) of our recommendations.

  • The document we wrote was quite purposeful in not telling engineers how to do alternative solutions or to dictate to BCA’s how to go about reviewing or approving alternative solutions. It was instead geared towards advising suitably competent engineers that alternative solutions of various types were on the table, and reminding them of a few key factors worthy of consideration.

  • These factors were the kinds of discussion items that came up often in the Working Group’s discussions and workshops, and reflected our experiences of performance based designs and alternative solutions prior to the release of the new framework in 2012. Considerations such as making sure deviations from acceptable solutions captured all of the downstream/holistic impacts on the rest of the compliance document rather than just focusing on the immediately obvious ones, sensitivity studies for various calculations or analysis undertaken, when qualitative or quantitative justification might be more (or less) appropriate, etc.

  • The discussions in the thread above on Factors (and margins) of Safety are quite valid, and I am glad this is being socialised. We chose not to include this in the short guidance document in any great detail, as it warranted separate treatment, and maybe some guidance of its own. One point we did chose to make though, was simply to remind engineers that the C/VM2 construct has Margins of Safety built in (somewhere), and that if you were considering an alternative solution which involved a deviation from this methodology in some way, then you needed to carefully consider how your changed input, acceptance criteria,or methodology might impact that inherent margin - and agree this with your regulatory stakeholders. In an ideal world, this should be well within the competence of a suitably experienced and qualified fire engineer to review, assess, propose and justify I think.

  • With regards to the FEB process, I see the guidance is a little inconsistent on whether it is recommending and FEB process be undertaken, or mandating it (although it seems to be more biased towards recommendation in its selection of wording). As I’m sure most of you are aware, I am a strong supporter of the FEB process in all performance based design anyway (with that process being scalable depending on the type or complexity of alternative solution being proposed), and I make no apologies for that…so am not really that fussed that the guidance mentions it as often as it does.

So overall, its fair to say I’m quite happy this document has been produced, and that there is now no (well… less) uncertainty on whether alternative solutions and deviations from compliance documents etc are possible. This removes the current frustrations I/we experience around being locked into a “fully comply with compliance document or bust” approach, and kind of opens up the opportunities for methodology we had prior to 2012. This is of course coupled with some timely reminders on key considerations involved with progressing and de-risking alternative solutions and approvals.

Sure…we can can find various clarity issues by drilling into the detail of every sentence, but I prefer to take this document as the face value opportunity it provides around freeing up my approach to alternative solution fire engineering design.

There are therefore a few actions to progress I think…for anyone (or any professional body) who has the time and motivation to take a lead on this…such as:

  • Guidance on factors and margins of safety
  • FEB guidance
  • Reviving some of the dialogue on various methodologies and approaches various issues, deviations, and performance base designs raise (both in forums like this, and academically through research etc)
  • Some BCA advice on what types of qualification, experience, competence etc would be appropriate for different types of alternative solutions (both design and review)
  • Factor/Margin of Safety guidance

These too, are simply opportunities to progress as an industry…so I look forward to the conversation around getting them underway.


Hi Alan,

Both SFPE International and SFPE NZ Chapter strongly recommend the FEB process.

Regarding the other items, they are important for the successful design and construction of buildings. If a fire engineer is not competent to carry some or all of them out or does not want to do it for commercial reasons, you are right the Building Act does not force them to do it. However it is important to tell the client and BCA that you are not providing those services and that someone else needs to cover them so that alternative arrangements can be made.

Since both CPEng and Fire designers are welcome to be members of the SFPE Chapter, the same recommendations would apply to Fire Designers to advise their clients and the BCA what their areas of competency and commercial scope is, along with the other fire safety aspects that will need to be carried out by others. Clients are generally not fire engineers so they will not realise that a limited scope of engagement is not the full scope if it is not spelled out for them.



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Thanks Michael,

I agree that the FEB is good practice, I know I was one of the few who started the idea of the FEB in the UK years ago…but it still can not be enforced like the BCAs and some of the other stakeholders are doing.

As for the other items I am not at all confident that there is a fire engineer in NZ that is competent on all aspect of construction or architectural design, so it is not a cleaver idea to try to do a role for “commercial” reasons. It smacks of selling your soul for a dollar and not realising the liability or the legal implications of that action. Simply put as CPEng we are possibly being forced to work outside our competency, being forced to accept liability and work in a way that breaches the Building Act… Interestingly I am not sure how many non CPEng are members of SFPE, but that is irrelevant as they still are not being obliged by some councils (Auckland for example) to sign off PS4 and do the rest of the other items…I have proof if needed…

If it is not required buy the Act we can not be obliged to provide it and should not be forced by commercial pressures to do it either. Others have roles to play in their respective fields Architectural design and co ordination (Architects), Processing and granting consent (BCA), Inspections (Councils), FENZ (limited to section 46 and 47 of the Act)…they should all step up and do their roles within their own scope and things will sort themselves out…

Hi All
The FEB was originally produced by the Fire Code Reform Centre in Aus, which I was a member of. It was produced to give the stakeholders an opportunity to have an input into the design parameters. IT WAS NEVER INTENDED TO BE A DESIGN DOCUMENT. Various administrations have bastardised it since that time, and now we have the situation that an ill defined document has become essential to undertake C/VM2 projects, and for it being demanded by BCA’s for alternative designs.
Any competent fire engineer should understand the difference between a briefing document and a preliminary design, which is what many councils and FENZ are expecting to see. We even have the situation where if FENZ have a look at a preliminary design for a project, they will actually call it an FEB. I suggest that all parties need to have a good look at the CIC Guidelines, which at least is understood by most parties to the construction process.
In regard to safety factors: I think it is an absolute hoot to think that BIA or DBH or MBIE have a clue as to what the actual “built in safety factors” are. I have requested this information on multiple occasions, with the exactly the same response as I have received from MBIE in regard to a correction to the water supplies for fire fighting - NIL. In the absence of any published safety factors for ASX or VM, it is logical to assume that these do not exist. This immediately begs the question as to why alternative designs need to demonstrate safety factors. Think about the Mean Time To Failure (MTTF) for a fire alarm panel: There is no fire alarm panel generally sold in NZ that is in compliance with any level of ISO 13849-1, so immediately we have no ability to determine a safety factor for a design. A fire safety design is made up of 100’s of separate details, each of which has a MTTF, and none of which are commonly published or even considered. How do you tell if the door heater on an emergency escape door from a cold store has failed, and the door is iced up? You can do it, but it is up to the fire engineer to determine if it is required.
I have recently had a query from a reviewer as to why I chose a certain safety factor. I kept the safety factor, but removed all reference to it in the report, as grinding through the process of determining the reliability of every element in the design, and then applying a safety factor at the end is not justified for comparatively small jobs.
Bottom line:
FEB’s are not a design document, and should only contain the design constraints.
Safety factors, to the best of my knowledge, have never been determined for any versions of ASX or VM2. It is ludicrous to think that this work has been undertaken, and never published, as I suggest there are very few people in NZ who are competent to undertake the preparation of such a body of work.
Paul C