FW: Usage of LPG for metal cutting - Message is from an unknown sender

[Guest guest]

Regards,

Amish

Re: IS for Ladder

& Usage of LPG for metal cutting

Dear Mr.Kuldeep,

Its IS 3696 - Code of Practices for scaffolds and ladders.

Dear Friends & Respected

Engineers,

Can we have a discussion on usage

of LPG as an alternative for DA in metal cutting process.

Q No 1: Is

there any legal aspect that forfeit this?

Q No 2. Based

on the Explosive range LPG is found to be safer than DA, so can we

consider the usage of LPG for cutting as a safer practice?

Kindly please share ur opinions..

Regards,

Manikandan B

HSE Engineer.

kuldeep <princekuldeep> wrote:

Dear All,

Can anybody help me out in getting

IS for la

Thanks in advance.

Kuldeep.

Send instant messages to your

online friends < http://au.messenger.yahoo.com/ >

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[Guest guest]

Lot of discussion took place on this subject during July end. However I am just forwarding one mail which will be of use to you..

---------- Forwarded message ----------

Date: Jul 31, 2006 3:42 PMSubject: RE: FW: Usage of LPG for metal cutting - Message is from an unknown senderTo: panchapakesan krishnamurthy <k.panch15@...

>Cc: REC_HELPS

The following information are the probable reason for prohibiting LPG cylinder in our plant.1. High Expansion ratio, (Approx. 250 time in volume) Risk is high, Expansion ratio is less for Acetylene, comparatively low risk. 2. LPG being heavier than air will settle down in case of leakage posing greater risk of catching fire or even explosion. 3. LPG has very low dispersion rate, which mostly will lead to UVCE kind of explosion 4. LPG cylinders of any size or weight are constructed of thin walled MS sheet compared to acetylene cylinders making it more vulnerable to heat up easily in case of any spark falling on/over the cylinder. 5. No approved regulators are available in open market except with the cylinder suppliers' viz. IOC, BPCL, HPCL.

6. Single stage regulator is used in LPG cylinder; In Acetylene you have a key to open cylinder and regulator.7. LPG can get trapped in the cable trays / sumps in floor level

8. More over the calorific value of LPG is approx 1/3 rd of Acetylene. So volume of LPG for the required heat will be thrice and this will increase more handling / storage problems.

9. Ability to ignite & burn as a

deflagration.

10. Reports have suggested ignition sources as far a

s 200 m. from source of gas leakage. Fire can initiate and flash

back and reach the leaking source.

With regards,

Harichatan

From: indiansafetyprofessionals [mailto:

indiansafetyprofessionals ] On Behalf Of panchapakesan krishnamurthy

Sent: Monday, July 31, 2006 2:08 PMTo: Mehta, Mr. A (Amish)Cc: Indian Safety professionalsSubject: Re: FW: Usage of LPG for metal cutting - Message is from an unknown sender

Thanks for very good compilation.

You can also add the latest discussion point:

In the event of back fire, the chances of LPG cylinder getting exploded is higher than that of Acetylene cylinder as acetylene cylinder has an unique safety feature (fusible plug) to depressurise the cylinder.

With regards

On 7/31/06, Mehta, Mr. A (Amish) <amishm@...

> wrote:

Regards,

Amish

Usage of LPG for metal cutting - Message is from an unknown sender

Dear Mani, Kuldeep, Durairaj, Manikandan, Shridhar,Panchapakesan , Karthick & friends,

This debate is indeed at interesting corner. I am basically from LPG background so wud like to throw some light on the debate and clarify many of the questions raised so far .

Can LPG be used for metal cutting ?

Yes.

Which LPG can be used?

Many private LPG suppliers like

Super Gas , Shell etc provides LPG cylinders in various sizes for commercial / industrial purpose ( 17kgs / 33kgs ) . In general , one can use any LPG cylinders primarily not meant for domestic purpose egg. One can not use 14.2kg of LPG cylinders being marketed by PSUs.

How can we store LPG cylinders or is it allowed?

Rules doesn't permit storage of unconnected cylinders more than aggregate capacity of 100kgs as per under mentioned rules / guideline

OISD-162, Clause 3.12:

As per the statutory requirements no explosive license is required for multi-cylinder installations. However, consumers having unconnected filled cylinders with more than 100kgs of LPG shall obtain Explosive license under Gas Cylinders Rules 1981

Gas Cylinder Rules, 1981, Chapter VII (Filling & Possession)

Rule 52:

No license is needed for filling and possession in cases where the quantity of gas stored does not exceed 100kg at any one time.

·

We can fabricate manifold system and use. Manifold system does not required any license provided it is meeting IS 6044 part I . Or

·

One can construct LPG storage godown and take license from explosives dept

·

Can keep all LPG cylinders connected to the points ( isolated one )

Equipment cutting torch, nozzle, regulators, FBA , hose and valve etc ??

·

Cutting torch is same irrespective of type of fuel.

·

Nozzle is required to be change which are standard and available in market

·

Hoses should comply at least IS 9573 ( for LPG )

·

High pressure regulators are available in the market from reputed suppliers like Vanaz, Kosan , United , Nirmal etc. In case required these can be available on tailor made basis too. Also some of LPG suppliers like Super Gas, get this manufactured especially suited for metal cutting ( high pressure ) and supply to it's customers.

Is LPG safe compared to Acetylene ?

Technical comparison wrt to safety of various fuels acetylene , Propane, Natural gas and proplylene ) have been attached.

Based on fwg parameters , it can be said that LPG is safer than Acetylene

Explosive limit Pressure under which product stored in cylinder

Acetylene 2-80 21kg / cm2

LPG 2-10 6-8 kg / cm2

Any other operational issues ?

Practically LPG can be used to cut upto 80-100mm plate thickness.

o

Flame temp - Acetylene produces the highest flame temperature of all the fuel gases. The maximum flame temperature for acetylene (in oxygen) is approximately 3,160°C compared with a maximum temperature of 2,810°C with propane.

o

The marginal higher flame speed and the higher calorific value of the primary flame (only inner cone & not total ) (18,890kJ/m

3 compared with 10,433 kJ/m 3

for propane) produce a more intense flame at the surface of the metal reducing the width of the Heat Affected Zone (HAZ) and the degree of distortion.

Is LPG economically viable against Acetylene ?

LPG / Propane produces a lower flame temperature than acetylene (the maximum flame temperature in oxygen is 2,828°C compared with 3,160°C for acetylene). It has a greater total heat of combustion than acetylene ( heat is generated mostly in the outer cone )

Total heat liberated per unit volm of fuel is higher in LPG than acetylene

.. Detailed calculation is attached in the sheet. Usage of LPG will save approx 25% of than the cost of using acetylene

I hope this will clarify lot of questions raised. Please revert in case of any further query related to metal cutting or wrt LPG

Regards,

Amish

Manager – Technical

SHV Energey Pvt Ltd

SUPER GAS

-----Original Message-----From: Sridhar B [mailto:

sridharb@...] Sent: Saturday, July 29, 2006

9:12 AM

To: panchapakesan krishnamurthy; KV SubbarayuduCc: S.Sel...[Message clipped] -- K.PANCHAPAKESANDY. MANAGER (SAFETY)WHEELS INDIA LTDPADICHENNAI - 600 050MOB: 98409 94397

-- K.PANCHAPAKESANDY. MANAGER (SAFETY)

WHEELS INDIA LTDPADICHENNAI - 600 050MOB: 98409 94397