Class 150 Manway Lock?

[jlcochran1]

We have a customer requesting manway locks for a previously fabricated pressure vessel. Anyone aware of "off the shelf" Manway locks for fabricated manways from class 150 RFSO and Blind flanges?

I can think of ways a lock clip could be fabricated or perhaps modify a bolt. However curious to know if I am reinventing the wheel if something already commercially available that doesn't require welding such as a clamp on device.

 

[jte]

Sounds like someone is taking "lockout/tagout" a bit too literally!

As for reinventing the wheel... Perhaps you could modify an automotive locking lug nut. Something like this:

http://www.autobarn.net/mcwhloandlug.html

... or this...

http://www.masterlock.com/cgi-bin/product_detail.pl?top_id=B71&sub_cat_id=D262&template=app

... or cover the whole stinkin' flange (beware thermal issues here) with this:

http://www.safetyseries.com/apps/safetyseries/products/items.jsp?id=10128&sids=10128

jt

 

[dugal]

Not sure there is enough info in your description of what you need.... Is the lock out needed to prevent/warn people from opening the flange or perhaps closing it after it has been opened for a reason ?? Also to be "politically correct" these days we refer to these flanges as "access flanges" "Manway" flanges is a terminology from the past.
Cheers
Doug

 

[jlcochran1]

Dugal,

Lock to prevent unauthorized access.

Understand outdated terminology, after 25 years old habits hard to break. The majority of our customers still use the term "manway", typically our drawings match customer nomenclature. This is probably one example where they should be corrected. A few customers do call out as "access opening" however.

JLC

 

[SnTMan]

jlcochran1, this requirement could make sense for some kind of quick opening closure, but for a bolted flange? It wouldn't seem possible to open it quickly or accidently.

Do they have unauthorized persons going around unbolting stuff?

Regards,

Mike

 

[jte]

JLC-

I guess a simpler way would be to drill a hole in the stud just past the outer end of the nut and put a padlock through it. Do that to two opposing studs (four holes, one on each end of the stud) and you're done. The hole doesn't need to be centered so an ordinary padlock could work.

jt

 

[jlcochran1]

SnTMan,

First request I have had for something like this. Actually the last time as I was at this plant it had some of the tightest security I had seen. Difficult enough for their own employees to get in, let alone visitors.

jte,

We had thought of the stud, (or PV grade bolting w/padlock on one side), but wanted to see if we were making too complicated. It doesn't sound like this a common request.

Thanks for all of your input. We will try to obtain more information from the customer, such as what is driving the request and what they have seen done before. We have built several vessels for them thru the years, but this is a new one.

 

[dugal]

Sounds like someone in the past opened an access flange without proper approvals from the controlling authority. They might have had a close call of some sort from this event and as part of an investigation a locked flange was proposed as one of the corrective actions. I am only speculating here.
I do recall at work once a pressure regulating valve stem that we built a metal cover for with a registered lock on it. The regulating valve was a poor design and if you turned the head with a wrench too far the stem would pop right out of the valve spraying pressurized oil everywhere.
The valve was eventually replaced with a better design.
I am thinking you or your customer could build a padalocked clamshell type of ring cover that would conceal the flange nuts.
Cheers

 

[vesselguy]

Could your customer be thinking of a GD Bandlock Closure that is used commonly on pig launcher, etc.?

http://www.spxprocessequipment.com/sites/gdengineering/bandlock2.asp

If not, like the other guys says, just weld two clips with a hole in them and put on a combination lock and charge your customer $3000 for it as an engineered product. LOL.

As for the politically correct terminology of "access opening" instead of "manway" as dugal said above,....please give me a break. There's enough PC BS in the world already.

 

[arto]

The gearbox mil std [MIL-G-17859]had a criteria that > 12 bolts didn't need a lock {the stupid guy would be too lazy to loosen all those bolts?}
Maybe you could you a similar criteria?

 

[gr2vessels]

The locking issue is not new and not necessarily regarding the prevention of a criminal act, tampering with the inspection opening to place a bomb inside.
The type of cover mentioned by dugal prevents the loosening of the manway bolting, with the vessel under pressure, when half of the tight bolts would not support the cover, hence the cover could be blown off. A plant logbook will probably provide a check list, to ensure the vessel being fully depresurised before unlocking the clamshell ring, to access the manway cover bolting.
This will also be deterrent for the would be terrorist.

cheers,

gr2vessels

 

[dugal]

Another avenue to look at is the problem in some remote petroleum pipelines where theft of oil and piping xmas trees ocurr. A lot of the petroleum companies have put locking devices on their flanges to prevent opening or loosening.
Cheers