Spark arresters for vehicle having catalytic convertor

[sujay]

Hi friends,
Could anybody pl help me.

I have received query from my plant people regarding need of spark
arrestor for vehicles having catalytic converter. [for vehicles plying
inside hydrocarbon handling areas]

Is it required ?

Requesting your views.

Regards,
Sujay

[Terje]

Hi Sujay,

I do not have very much knowledge regarding regulations for vehicles
inside hydrocarbon handling areas, but I'll try to give you my two
cents worth here.

Regular vehicles (cars and trucks) typically have a long exhaust and
baffled mufflers which act as a spark arrestor. Especially in
combination with a catalytic converter which also acts like a spark
arrestor itself. I see little reason for demanding an additional spark
arrestor, unless you need to be triple safe regarding sparks from
vehicles.

I do however know that there are requirements in some parts of OSHA,
for instance in 1910.265(c)(30)(ii) regarding saw mills. Sadly I don't
remember the standard for sites handling hydrocarbons. You may find
some information in other OSHA standards, such as 1910.178 which
applies to fork trucks, tractors, platform lift trucks, motorized hand
trucks, and other specialized industrial trucks powered by electric
motors or internal combustion engines.

Regarding sites handling hydrocarbons I believe it is quite common to
provide spark arrestors for internal-combustion engines. Some, such as
well sites, often prohibit vehicles with catalytic converters from the
immediate vicinity of the rig. The reason for this is, as I have been
told, most often because of the radiant heat from the exhaust system
which may pose a fire hazard as an ignition source.

There should be someone else here that can provide better answers than
me. Look forward to reading these, as I feel I too need more
information.


Regards,
Terje

[sujay]

thanks very much,

but my doubt is - if it is not allowed near well, how can it be
allowed inside hydrocarbon areas, both areas are having similar
hazards.

regards,

> > Sujay- Hide quoted text -
>
> - Show quoted text -

[Terje]

Hi again Sujay,

As I stated in my previous answer - this is somewhat outside my area
of expertise. Is your company regulated by OSHA or EU-OSHA? If so,
they should be able to help you. If you are not, they should at least
be willing to inform you about their equivalent regulations.

My deduction regarding your predicament is something like this:
* There is a concern amongst your plant people regarding sparks in
hydrocarbon areas
* You can not find any regulations for hazards related to sparks
from vehicles
* But you find similarities regarding hazards with well
sites
* I would apply regulations for well sites to your
hydrocarbon areas

On the other hand; I assume that you have conducted a risk assessment
for your hydrocarbon areas. If this has been done correctly it should
show if you have the need for spark arrestors or not - never mind the
potential regulations. Sometimes you have hazards at a site even when
there are no regulations for them - and then you have to try to
minimize or remove these anyways.

From the risk assessment you should get your answer, there are
typically three alternatives:
1. No relevant hazard --> Conduct business as usual, i.e. do nothing
2. Medium level of hazard --> Fit spark arrestors on vehicles
3. High level of hazard --> Prohibit vehicles from the area


Best regards,
Terje

[sujay]

Thank you very much !

But, for conducting RA also, I need to know - technically - whether
there is any chance that spark will come out from a Cat.Conv.
[knowledge of internal construction of cat.conv]

By looking at OSHA regu, it seems that cat. conv is prone to heat up
and act as ignition source, rather than it allows any spark to come
out. If so, we should consider it - straightway - as ignition source
and should not bother about its capability [rather limitation] to
allow a spark to pass/hold.

Am I on right direction ?

Regards,
Sujay.

> > > - Show quoted text -- Hide quoted text -

[Terje]

Hi there Sujay,

I believe that you are on the right track.

Considering my first response to your post I claimed that to my
knowledge there is little chance of getting sparks from a regular
vehicles (cars and trucks) because of their long exhaust, baffled
mufflers and combination with a catalytic converter. But - for the RA
- you can not claim that there is no chance of sparks. This means that
you will get a low probability but a very high/catastrophic
consequence.

My thoughts are that the greatest ignition source regarding such
vehicles is the radiant heat from the exhaust itself and the catalytic
converter. This will maybe give you a medium to high probability and
also here a very high/catastrophic consequence.

Depending on the accept criteria you set in your RA you might allow
vehicles in your carbon handling area with concerns to the low risk of
sparks from the exhaust, but you most probably will not allow them
because of the radiant heat which poses a high risk.

There are still some questions you have to consider before making your
decision, amongst others are:
* At which temperatures does your mix of hydrocarbons ignite?
* At what concentration do they need to be mixed with air in order to
be able to ignite?
* How often do you experience hydrocarbons in the area you use
vehicles?
* How often are there vehicles in these areas?
* What kind of temperatures can you expect from the exhaust and from
the catalytic converter?

This will give you a final question which will be something like this:
* How likely is it that you will have hydrocarbons in the area at the
correct mix with air in order to ignite and at the same time have a
vehicle with a sufficient temperature radiating from its exhaust/
catalytic converter to pose as an ignition source?

Hopefully you will now have enough information in order to make a
decision whether to allow or prohibit vehicles in your hydrocarbon
handling areas.

Please keep me informed about your progress in this matter. Good luck!


Regards,
Terje

> > - Show quoted text -– Skjul sitert tekst –
>
> – Vis sitert tekst –