[roc-chat] Re: New 'mass launch' rules
- From: Allen H Farrington <allen.farrington@xxxxxx>
- To: roc-chat@xxxxxxxxxxxxx
- Date: Fri, 20 Apr 2012 18:42:13 -0700
I have been looking into this extensively in preparing our BLM permit Event
Operations Plan so I just happen to have recent knowlege (and a copy of the
codes). One of the advantages of being a member of ROC (or flying with us on a
daily basis) is that we work with NAR and BLM, etc..., to keep you from having
to worry about all of this. ROC's range layout conforms to the rule changes
unless we decide to hold a mass launch (>10 vehicles) of M-to-M two stage
rockets. That's the only combination that we don't cover.
For those of you that are interested in the explanation, here are the details:
Both NFPA 1122 and 1127 have three sets of "safe distances" outlined in the
codes.
1) Launch Site Dimensions
This is the one that is based on altitude, not on impulse. It is used to cover
the amount of room you need to fly high and recover rockets within a defined
airspace. Since ROC maintains an FAA Waiver, we are exempted from the NFPA
table limits and instead use the factor of 1/2 of our waiver altitude. Since we
maintain the ability to have a 20K foot call-in, we have to make sure that
there are no occupied structures (not including Porta-Potties ;-)) within a 5K
foot radius of the range head (10K diameter). It is actually OK for Hwy 247 to
run through the middle of our "defined launch site".
2) Launch Pad Clear Distance
This is a ground fire-related distance that we traditionally ignore because we
launch in a vegetation-free area, but NPFA defines that you can't have
ignitable materials on the ground within a certain distance from the launch
pads. That distance is determined by the motor impulse. It is possible to get
confused about all this 1.5 times stuff because in this section of the code,
sparky motors are required to have 1.5 times the table distance. Again, the max
distance for an N equivalent impulse is 125 ft (or 200ft for sparkys). We
easily meet this.
3) Safe Launch Distance for Spectators and Participants
This is the one that is being modified. There are defined distances in both
NFPA 1122 and 1127 for how far you have to be from a launch pad when you ignite
the motor. This distance ranges from 15 feet to nearly 1500 feet depending on
impulse. For complex rockets, the distances are "one impulse level higher" if
you look at the table. This works out to be about 1.5 times. Since ROC uses a
range layout that allows folks to be at one set of pads while the other are
launching, we have a range layout that accommodates these distances. (except
for the aforementioned M-to-M, 2 stage, Mass Launch). In any case, the absolute
maximum distance required for any combination in CA is about 1/2 a mile (2250
ft). Other states allow larger impulses and therefore their ranges might be
larger.
Now given all this, the ROC board is reviewing our current range layout and
placement on the BLM square of the lakebed and using the new recommended wind
allowances guidelines from a NAR safety study may make some changes. Rest
assured that we'll be in compliance as we have to keep things correct for our
insurance to be in force.
Allen
On Apr 20, 2012, at 6:18 PM, Wedge Oldham wrote:
> Taking David's post as gospel; to launch the entire front row of Estes Alphas
> on C6-7s would require the front row to be 3000 feet from the flightline.
>
> On Apr 20, 2012 6:14 PM, "Wedge Oldham" <wedgeoldham@xxxxxxxxx> wrote:
> Not to argue needlessly but; David stated 1.5 times. Allen you state 0.5
>
> But both state EXPECTED ALTITUDE. Assuming Allen is correct; an expected
> altitude of 10000 feet would require 5000 feet of cable. Currently the best
> ROC has is 800 feet.
>
> I don't see how ROCs existing layout already takes this into account.
>
> Wedge
>
> On Apr 20, 2012 4:05 PM, "Allen Farrington" <allen.farrington@xxxxxx> wrote:
> Nope. The change is to treat mass launches of that size as if they are
> complex rockets on terms of standoff. This does not alter the range sizes
> (different table) which is where the 1/2 the maximum altitude rule comes in.
>
> Since ROC's range layout already accounts for complex rockets, this doesn't
> really affect us.
>
> During our stand down period, the ROC board is reviewing our range layout and
> procedures to continue our safety focus.
>
> Allen
> Terseness and mis-spelling courtesy of my iPhone
>
> On Apr 20, 2012, at 3:07 PM, Wedge Oldham <wedgeoldham@xxxxxxxxx> wrote:
>
>> So Goblins on Ks with an expected altitude of 10k need to be setup 15000
>> feet from the flightline?!?!?
>>
>> On Apr 20, 2012 2:53 PM, "David Erbas-White" <derbas@xxxxxxxxxxxxxxxx> wrote:
>> Don't know if folks have seen it yet, but as of this summer the new
>> guidelines for mass launches (anything more than 10 rockets) simultaneously
>> means the stand-off distance is 1.5 times expected maximum altitude (NAR
>> rules, but drawn from NFPA, so I would expect TRA to follow suit if they
>> haven't done so already).
>>
>> Guess the 'K' Goblin drag races will be but a memory, now...
>>
>> David Erbas-White
>>
>>
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>>
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