LPG Operations – Core Vocabulary Flashcards

A comprehensive set of vocabulary flashcards covering abbreviations, equipment, safety devices, physical properties, operational procedures, and fire-fighting terms essential for Bharat Petroleum LPG operations.

CCOE

Chief Controller of Explosives – Indian regulatory authority for pressure vessels and hazardous materials.

BIS

Bureau of Indian Standards – National body that formulates IS codes and certifies products.

CVT

Compact Valve Tester – device for detecting LPG valve leakage (sensitivity 0.5 g/h).

ELD

Electronic Leak Detector – hand-held device for sensing flammable-gas leaks.

EPD

Electro-Pneumatic Detector – rate-of-rise heat detector set to 10 °C per minute.

QBD

Quartzoid Bulb Detector – fixed temperature (68 °C) sprinkler/heat detector using a glass bulb.

LPG

Liquefied Petroleum Gas – pressurised mixture mainly of butane and propane.

EFCV

Excess Flow Check Valve – closes automatically when flow exceeds preset limit to prevent large releases.

SRV

Safety Relief Valve – lifts at 110 %–120 % of design pressure to protect vessels from over-pressure.

TSV

Thermal Safety Valve – relieves liquid LPG trapped between two closed valves due to thermal expansion.

LEL

Lower Explosive (Flammable) Limit – minimum vapour concentration in air (LPG ≈1.5 %).

HEL

Higher Explosive Limit – maximum vapour concentration that can burn (LPG ≈9.5 %).

SMPV Rules

Static & Mobile Pressure Vessel Rules 1981 – govern design, fabrication and operation of LPG vessels.

OISD-144

Oil Industry Safety Directorate standard for layout and operation of LPG bottling plants.

VSCR

Vasudevan Safety Committee Report (1983) – key recommendations on LPG plant safety; suggests 80 m green belt.

BLEVE

Boiling Liquid Expanding Vapour Explosion – catastrophic vessel failure when LPG suddenly flashes to vapour.

UVCE

Unconfined Vapour Cloud Explosion – ignition of dispersed LPG cloud in open area.

Green Belt

80 m (VSC) vegetated buffer surrounding plant to keep outsiders away and dilute leaks.

Internal Safety Audit

Annual, multi-discipline audit by regional team covering operations, engineering and safety.

External Safety Audit

Biennial audit of plant by OISD to verify compliance with standards.

Tell-Tale Clock

Security clock that records guard patrol timings via key punches on revolving dial.

National Safety Day

4 March – anniversary of National Safety Council; promotes safety awareness.

Fire Services Day

14 April – commemorates 1944 SS Fort Stikine explosion; observed as Fire Prevention Day.

Fire Classification (India)

Four classes based on material: A-solids, B-flammable liquids/gases, C-electrical, D-metals.

Hazard Zone-2

Area where flammable vapours are present only under abnormal conditions.

HAZCHEM Code

Emergency response coding devised by London Fire Brigade; LPG code 2WE.

Auto-Ignition

Self-ignition of product heated to its ignition temperature without external spark/flame.

Dead-Weight Tester

Calibration device that uses known weights on a piston to generate precise pressure for gauge testing.

Flameproof Equipment

Enclosure withstands internal explosion without transmitting it to outside mixture.

Intrinsically Safe Equipment

Design limits electrical/thermal energy so sparks cannot ignite flammable mixture.

UN 1075

United Nations number identifying LPG for transport and documentation.

Gas Test Certificate

Document issued by Location Gas-Safety Inspector certifying area is gas-free for maintenance.

Buffer Zone

Additional green-belt area beyond normal safety distance to limit off-site impact.

LFL

Lower Flammable Limit – synonymous with LEL.

Bulk Vessel

Pressure vessel >1000 L water capacity for LPG storage or transport.

Cylinder

Portable pressure container ≤1000 L water capacity for domestic/industrial LPG.

Earthing

Provision of low-resistance path to ground to drain static/electrical currents.

Filling Ratio

Weight of LPG filled ÷ weight of water cylinder holds at 15 °C (India ≈0.42).

Hot Work

Maintenance activity producing flames, sparks or heat capable of igniting vapours.

Reid Vapour Pressure

Vapour pressure (psi) of petroleum product at 100 °F measured in Reid apparatus.

Flash Point

Lowest temperature at which product vapours flash momentarily when ignited.

Fire Point

Temperature at which product sustains continuous combustion after ignition.

Petroleum Class A

Flash point <23 °C; LPG and petrol fall in this class.

TLV

Threshold Limit Value – airborne concentration safe for 8 h/day, 48 h/week exposure.

Hot Work Permit

Authorisation (pink, 3 copies) for jobs involving sparks/flames in hazardous area.

Cold Work Permit

Permit for non-routine maintenance without ignition sources.

Vasudevan Safety Committee

1983 MOP&NG panel formed post-Shakurbasti fire to study LPG plant safety.

Malhotra Safety Committee

1986 committee to review implementation of VSC recommendations; suggests 30 m green belt.

DPR

Domestic Pressure Regulator – reduces cylinder pressure to 300 mm water column.

DBC

Double Bottle Connection – domestic two-cylinder LPG installation.

LERC

LPG Equipment Research Centre, Bengaluru – tests and certifies LPG hardware.

Ignition Energy

Minimum spark energy needed to ignite flammable mixture.

NFPA

National Fire Protection Association – US body publishing fire codes (colour triangle logo).

Domestic LPG Composition

Approx. 55 % butane, 45 % propane in Indian cylinders.

LPG Density (liquid)

≈0.545 kg/L at 15 °C (500–545 kg/m³).

LPG Calorific Value

≈10,900 kcal/kg.

LPG Expansion Ratio

Liquid expands about 250 times when vapourised at atmospheric conditions.

Ethyl Mercaptan

C₂H₅SH odorant added to LPG at ≤1/5 LEL (≈20 ppm) for leak detection.

Boiling Point – Propane

-42 °C at 1 atm.

Boiling Point – Butane

-0.5 °C at 1 atm (ceases to vaporise below –17 °C).

Hazard of Rich Mixture

LPG concentration above HEL will not ignite until diluted into flammable range.

HAZCHEM 2WE

LPG response code: use water fog, dilute spill, consider evacuation.

Domestic Cylinder Water Capacity

33.3 L; net LPG 14.2 kg.

Tare Weight

Weight of empty cylinder with valve; domestic range 14.3–18.5 kg.

VP Ring

Valve Protection Ring – top guard preventing impact damage to valve.

Hydrostatic Test (cylinder)

25.35 kg/cm² for 30 s; first at 7 years, then every 5 years.

Valve Torque

145 ± 15 ft-lb (≈20 kg-m) using torque wrench when fitting valve.

SC Valve

Self-Closing cylinder valve (spring-loaded spindle).

MB Valve

Mechanically Balanced valve; spindle load balanced for easier operation.

Purging

Evacuating air and introducing LPG vapour to avoid explosive mixtures before first filling.

NGT Threads

National Gas Taper threads – ¾" BSPT on cylinder valves (13 turns, 5–6 visible).

Safety Cap

Plastic/metal cap over valve; withstands 17 kg/cm² and prevents dust entry.

Cylinder Filling Tolerance

±150 g net weight as per Legal Metrology Act.

Spurious Cylinder

Non-standard or counterfeit cylinder failing design, markings or material specs.

ROV

Remote Operated Valve – quick-shut plug valve actuated by air/spring via solenoid.

Rochester Gauge

Float-type percentage gauge on bullets/spheres for approximate liquid level.

Magnetic Dip Gauge

Accurate level gauge using magnetic follower on tape/rod; basis for stock records.

Fixed Ullage Gauge

Dip tube set at 87 % volume on bullets; emits vapour until over-filled, then liquid.

High Level Alarm (HLA)

Audio/visual alarm at 85–87 % volume to prevent over-filling of vessel.

Multi-Port SRV A-8574M-200

Rego 4-port SRV, 4" 300-lb, set 200 psi (13.8 kg/cm²), 23,400 CFM air capacity.

Kerb Wall

30–60 cm brick wall around storage area to contain spilled LPG.

Vapour Seal

Water trap in drainage to prevent LPG vapour escape through sewers.

Design Code – Bullet

ASME Sec-VIII Div-1 / IS 2825, design 16.1 kg/cm², –27 °C to 55 °C.

Design Pressure – Cylinder

16.9 kg/cm² (120 psi) at 65 °C.

Cavitation (pump)

Formation and collapse of vapour bubbles in pump due to low suction NPSH.

Mechanical Seal

Leak-proof shaft seal using lapped faces (stationary carbon + rotating metal).

NPSH (R)

Net Positive Suction Head Required – minimum head to avoid cavitation.

Knock-Out Drum

Separator on compressor suction removing entrained liquid LPG.

Load / Unload Compressor

Capacity control by holding suction valves open (unload) or closed (load).

Piston-Rod Run-Out

Axial/radial deviation of rod; measured with dial gauge to ensure alignment.

Splash Lubrication

Crankcase oil system where crank webs fling oil onto components.

Force-Feed Lubrication

External pump feeds metered oil to cylinder walls and bearings.

EFCV Chatter Range

Flow band between start-to-close and fully-closed; typically ±3 % of set flow.

Tremcard

Transport Emergency Card carried in T/L; lists cargo, hazards, PPE, actions, contacts.

Master Switch (T/L)

Cabin battery isolator that cuts all electrical circuits during unloading.

Rotogauge

Rotating tube gauge on T/L showing liquid %; set to 100 % vapour while in transit.

Hydrotest Pressure – LPG Hose

25 kg/cm² quarterly; reject if elongation > +3 % or < –1 %.

Spark Arrestor

Mesh device on diesel exhaust preventing emission of incandescent particles.

Chain Conveyor

Powered conveyor moving cylinders through carousel; telescopic version extends into truck.

Corken Compressor

Vertical, oil-free LPG reciprocating compressor (ESH-1) with unloader pistons.