LPG – Liquefied Petroleum Gas

& Gas Detection System

– LPG & Gas Detection System,

Installation, Testing & Commissioning, design, Calculation.

Prepared By: Monzer Salahdine

Introduction

LPG System used to supply : LPG: Liquefied Petroleum Gas

I. Building – residential – kitchens.

II. Restaurants, industrial kitchens.

III. Laboratories, medical collages.

IV. Boilers.

V. Cars.

Introduction

LPG, Gas detection Systems:

I. LPG – Mechanical: Piping, Solenoid, Outlets.

II. Gas Detection System, Sensors, Panels.

LPG, Code and Standards:

1. NFPA 58: Liquefied Petroleum Gas Code.

Schematic Module

PIPES ASSETS

LPG & Gas Detection System as below procedure:

TESTING &

COMMISSIONING

MAINTENANCE

& OPERATION

Maintenance Installation & Commissioning

Introduction What is LPG:

A - Liquefied petroleum gas or liquid petroleum gas (LPG or LP gas), also referred to as simply

propane or butane, is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances,

cooking equipment, and vehicles.

B - Varieties of LPG bought and sold include mixes that are primarily propane (C3H8), primarily

butane (C4H10) and, most commonly, mixes including both propane and butane.

C - LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and

43.5 MJ/kg for premium grade petrol (gasoline). However, its energy density per volume unit of 26

MJ/L is lower than either that of petrol or fuel oil, as its relative density is lower (about 0.5–0.58,

compared to 0.71–0.77 for gasoline).

Introduction What is LPG:

D - As its boiling point is below room temperature, LPG will evaporate quickly at normal

temperatures and pressures and is usually supplied in pressurized steel vessels. They are typically filled

to 80–85% of their capacity to allow for thermal expansion of the contained liquid. The ratio between

the volumes of the vaporized gas and the liquefied gas varies depending on composition, pressure, and

temperature, but is typically around 250:1. The pressure at which LPG becomes liquid, called its vapor

pressure, likewise varies depending on composition and temperature; for example, it is approximately

220 kilopascals (32 psi) for pure butane at 20 °C (68 °F), and approximately 2,200 kilopascals (320 psi)

for pure propane at 55 °C (131 °F). LPG is heavier than air, unlike natural gas, and thus will flow

along floors and tend to settle in low spots, such as basements. There are two main dangers from this.

The first is a possible explosion if the mixture of LPG and air is within the explosive limits and there is

an ignition source. The second is suffocation due to LPG displacing air, causing a decrease in oxygen

concentration.

E - Commercially available LPG is currently derived from fossil fuels. Burning LPG releases carbon

dioxide, a greenhouse gas. The reaction also produces some carbon monoxide. LPG does, however,

release less CO, 2 per unit of energy than does coal or oil. It emits 81% of the CO

2 per kWh produced by oil, 70% of that of coal, and less than 50% of that emitted by coal-generated

electricity distributed via the grid. Being a mix of propane and butane, LPG emits less carbon per joule

than butane but more carbon per joule than propane.

Introduction

Odor Of LPG:

In their natural state, LPG (Propane and Butane) and Natural Gas

(Methane) are all odorless gases. The distinctive smell that people

associate with these gases is actually added to them as a safety

measure.

For many decades, the gaseous fuels industry has added odorants to

LPG and Natural Gas so that people can detect gas leaks with nothing

more than their noses. Without the addition of an odorant, leaking

gas could collect without being detected. This would create a

dangerous condition that could lead to an explosion or fire.

Introduction

LPG – schematic – residential example:

Gas Detector Of LPG at low level ( LPG heavier than

air).

Gas Detector Of Natural Gas and Coal gas at High

level (Air heavier than Natural Gas & Coal Gas).

Introduction

LPG – schematic – residential example:

Training Module In case of gas leakage inside the area (Kitchen, Lab), the gas sensor will

be activated.

When sensor activated, it will send a signal to the control panel which

will treat it as leakage inside the lab.

The panel will give signal to the solenoid valve to close immediately

(safety issue) to make sure no more gas flow to the area.

The panel will give another signal to the siren light (alarm, mean there

is leakage).

The panel will give signal to fire alarm system which will deactivate the

main solenoid valve of LPG of entire building(safety issue).

The panel will give signal to BMS system to notify to the operator

(maintenance team) that there is a gas leakage.

The operator (maintenance team) has to check if there is leakage or any

of outlet open and to close it immediately.

When make sure that no more gas leakage inside the lab, the operator

to make reset for the panel which will activate the system and the gas

flow inside the lab, and to reset the solenoid manually.

In case of fire alarm in the building, the main solenoid will be shut off

(safety issue), once signal not disappear the system will be automatic ally.

Schematic Module

LPG Station

Main LPG panel, including solenoid and

regulator( up to 20 PSI) Solenoid Valve

SUB LPG Panel

Outlets Including Solenoid

& Regulator( up to

5 PSI)

Liquid Gas

6.9 Bars

5 PSI

Outlets

1.5 to 2.5 PSI

10-20 PSI

Schematic Module-Detection

detectors

Detection Control Panel SUB LPG Panel

Solenoid Valve

Siren light

Main LPG Panel

Fire Alarm Panel

BMS System –Monitoring

Only in case of leakage

Pipes

Pipes for LPG: black steel seamless SCH80, galvanized steel,

polyethylene (under ground) Or Copper Pipes Type K & L:

Black steel Pipes – seamless SCH 80, threaded

installed in double containment pipes for protection

or welding without double containment.

Copper Pipes Brazing and threaded for the fittings

( valves, Outlets).

Solenoid Valve

It is electrical control valve energized from

control panel to shut off the gas in case there is

leakage.

Solenoid valve is normally close, once the panel

energized the panel send signal to solenoid to

open.

In case there is leakage, the panel cut the power

to solenoid and became again closed ( solenoid

Spring Type).

Detector

Detectors for LPG SENSITROM brand or other.

Detectors installed at low level at 30 cm from finish floor level

and above ceiling in double containment or near the welding

joint,

Detector detect the LPG leakage and give signal to detection

control panel.

This sensor module utilizes an MQ-6 as the sensitive

component and has a protection resistor and an adjustable

resistor on board. The MQ-6 gas sensor is highly sensitive to

LPG, iso-butane, propane and less sensitive to alcohol,

cooking fume and cigarette smoke. It could be used in gas

leakage detecting equipment in family and industry. The

resistance of the sensitive component changes as the

concentration of the target gas changes.

Each detector will have an IP and address where all detectors

will be labeled and reflected the same label in LPG detection

panel- in case of leakage will knowing which detector giving

the signal and the location of each.

SIREN LIGHT

SIREN light for LPG SENSITROM

brand or other.

Once LPG system is activated, panel will

give signal to siren light to alert the area

about the LPG leakage( Visio and

Audio).

Wall mounted or ceiling mounted.

Detection Control Panel

Detection control panel for LPG SENSITROM brand or other.

When sensor level reach more than 10, alarm 1 will be activated( solenoid level

close but no alarm).

When sensor level reach more than 15, alarm 2 will be activated( solenoid

close, alarm occur).

Once sensor level reach more than 20 , alarm 3 will be activated ( solenoid

close, alarm occur, given alarm to fire alarm and BMS).

LPG Gas Panel

Ball Valve

Strainer

Solenoid Valve

Gas detector

Gas regulator

Pressure Gauge

Ball Valve

Gas Relief

Testing & Commissioning

The LPG system tested and certified by Third Party-

specialist in installation and commissioning of LPG system

and certified from NFPA58.

Below tools used for the tests:

Testing & Commissioning

Test Procedures:

The testing commissioning of LPG system follow the below

procedure:

1) Leak test( all pipes are tested by nitrogen for leak test).

2) Flushing( all pipes flushed by compressed air and nitrogen

to clean them from particles and humidity.

3) Cross test(valve test- when valve close, gases not allow to

reach to others connections.

4) Flow test.

5) Final leak test once open the LPG, testing by manual LPG

detector sensor.

Testing & Commissioning

Why we make the above test ??

Targets and goals of LPG tests:

1. To maintain the equipments life and saving

money.

2. To reduce the risk (avoid LPG leakages in

future).

3. Maintenance team to inspect and check in

daily basis to maintain the above two items

(check list).

Precautions & Recommendations

1. Once LPG detector detect a gas leakage,

system will be alert, all persons should leave

the room immediately.

2. Specialist of LPG system (maintenance

company) should investigate the cause of

leakage and rectify if any than to reset and re

open the LPG system.

3. Maintenance company to make a check list

for each panel in daily basis.

4. Damages pieces or sensors to be rectified

immediately to maintain secured areas.

Design & Calculation

Gas Demand ( Btu/h) – ASHREA:

Design & Calculation

Heating Value After Vaporization:

Design & Calculation

Storage Calculation:

a.) Estimate No. of Lpg outlets

1. FOUR GAS BURNER RANGE ON GAS OVEN = 1 OUTLET

2. GAS POT STOVE ON STAND = 1 OUTLETS

3. SMOOTH PLATE GAS GRIDDLE = 0 OUTLET

4.GAS BIOLING PAN = 0 OUTLET

5. BOWEL GAS FRYER = 0 OUTLET

b.) Design Datas:

1. 4 BURNER OVEN = 65,000 Btu/Hr

2. GAS POT STOVE ON STAND = 40,000 Btu/Hr

3. SMOOTH PLATE GAS GRIDDLE = 30,000 Btu/Hr

4.GAS BIOLING PAN = 30,000 Btu/Hr

5. BOWEL GAS FRYER = 30,000 Btu/Hr

TOTAL = 105,000 Btu/Hr

c.) Calculation of Lpg consumption/day:

3. LPG HEATING VALUE AFTER VAPORIZATION = 2,500 Btu/h/Ft³ FROM ASPE

4. SIMULTANEOUS USE FACTOR ( PEAK HOUR AT LUNCH ONLY ) = 60%

5. ASSUMED BURNER WORKING TIME = 6 Hrs./Day

( 2 hrs per meal serve)

TOTAL LPG CONSUMPTION PER DAY = 151 Ft³

CONVERTING CU FT OF VAPOR TO GALLONS (75 ft3 / 36.39) = 4 G/Day

USE STORAGE TANK FOR ONE WEEK = 110 L

Design & Calculation

Pipe Size – Steel Pipe Sch40:

LPG pipes size depend to the

following:

- Pressure inside the pipe.

- Pipe lengths.

Btu/h or KW will be reduced with

pipe length ( otherwise pipe size to

be increased – see below).

Design & Calculation

Pipe Size – Copper Pipe Type K:

Design & Calculation

Pipe Size – Copper Pipe Type L:

Design & Calculation

LPG Pressure Drop:

System On Photos

System On Photos

End