Methods of Gas Distribution
- Natural Gas is distributed through
pipeline transmission network
- LPG is distributed through
- Towns Gas (Manufactured Gas): No longer
used
Note: LPG and Natural Gas are naturally
odourless – a stenching agent is added to ensure leaks
are easily detected.
LPG Cylinders:
LPG Bulk Tank:
Gas Properties
| |
Natural Gas |
LPG (Liquefied Petroleum Gas) |
| Composition |
Methane CH4 |
Propane C3H8 Butane C4H10 |
| Source |
Occurs naturally in certain gas wells |
Product of oil refining, sometimes from gas wells |
| Density of gas |
Lighter than air (0.6 specific gravity) |
Heavier than air (1.5 to 2.0 specific gravity)
|
| Flammability |
5% to 15% gas in air |
2% to 10% gas in air |
| Transportation |
Transported as a gas |
Transported as a liquid |
Pressure / temperature relationship:
Gas Standards: Pipework Types
- Installation Pipework is the pipework
and accessories from the "point of delivery" (gas meter
or gas tank) up to and including the appliances
- Service Pipework is from (and including)
the point of delivery back to the tank or distribution
main
- Distribution pipework is the Bord Gais
transmission network
Relevant Pipework Standards
| IS 813 Domestic Gas Installations |
Domestic LPG and Natural Gas installation requirements
|
| IS 820 Non-domestic Gas Installations |
Non-domestic LPG and Natural Gas installation
requirements |
| I.S. 265, Installation of Gas Service Pipes |
LPG and Natural Gas service pipe requirements |
In addition to pipework, the above cover
appliance location, flueing, etc.
Relevant LPG Storage Standards
| IS 3216 Part 1, Code of Practice for the Bulk
Storage of Liquefied Petroleum Gas |
LPG tanks and includes suitable locations, separation
distances, etc. |
| IS 3216 Part 2, Code of Practice for the Bulk
Storage of Liquefied Petroleum Gas |
This part is similar to Part 1, but applies only
to garage forecourts |
| I.S. 3213, Code of Practice for the Storage
of LPG Cylinders and Cartridges |
Storage (NOT use) of cylinders at cylinder dealer
& distributor premises |
Note: Irish Standards are available from
the National Standards Authority of Ireland (NSAI), Ballymun
Road, Dublin 9, phone 01 8073800.
Pipework and Security: Pipework
Requirements
- Hoses (e.g. catering equipment) - condition
(cracks), suitability for LPG, sealing washers
- Flue systems
- Ventilation
- Isolation Valves (total system, each
appliance)
- Fixing supports & bracketing of pipework
- Other requirements are not easily inspected
or are not as critical
- see IS 820 for details
Note: Pipework does not need routine inspections
(after initial installation tests). Can be pressure tested
if leaks or deterioration suspected.
Gas Detection
- Gas detection is only required where
LPG equipment is installed in a basement or where pipework
with non-welded joints passes through a basement.
- Gas detection systems should be capable
of shutting off the gas supply from OUTSIDE the building.
- Can be linked in to main fire alarm system.
- Schools now need automatic pressure-testing
systems for bunsen burners and domestic cookers (appliances
without flame-failure devices).
Security
- If necessary, protect cylinders and tanks
against vehicular impact
- Where there is uncontrolled access
to the cylinders or tanks by the public, use a cage
or enclosure:
- Non-combustible construction
- Lockable
- Open construction or else ventilated
at high and low level
LPG Bulk Tanks
Note that tanks and cylinders are only filled
to approximately 85% to allow for thermal expansion of
the liquid.
LPG tank for forklift filling:
Typical tank valves:
Service valve:
Contents gauge:
Filler valve:
Pressure relief valve:
100 gallon tank:
100 gallon tank fittings:
Tank Separation Distances (simplified)
Distances to buildings, boundaries, and
fixed sources of ignition
| Tank size |
Without firewall |
With firewall |
| 100 gallon |
2.5m |
0.3m |
| Up to 1 tonne |
3m |
1.5m |
| Up to 4 tonne |
7.5m |
4m |
| Up to 60 tonne |
15m |
7.5m |
| Above 60 tonne |
Seek specialist advice |
Seek specialist advice |
Separation Distances from Other
Substances
| Substance |
Separation distance |
| Liquid Oxygen |
Normal separation distance subject to 6m min. |
| Flammable substances f.p. < 60C |
6m |
| Other flammable substances (most oil) |
3m |
| Toxic or hazardous substances |
Normal separation distance subject to 15m min.
|
Note: tanks are visually inspected by tanker
drivers on every fill. In general, full requalification
required every ten years. If customer-owned tank, customer
is responsible and must arrange it.
Types and Sizes of Cylinders
- Butane cylinders
- Usually 7 or 11Kg, self-closing valve
- Propane cylinders
- Manual-shutoff, handwheel valve
- 11Kg, 34Kg, 47Kg approximate sizes
- Forklift cylinders
- 15 to 20 Kg, self-closing valve
- Single handwheel valve or (more usually)
multiple fittings as on a large gas tank
Note: Cylinders owned by LPG companies are
visually inspected and leak-tested at every fill and requalified
every 15 years.
Cylinder types:
Butane cylinder valve:
Propane cylinder valve:
Automatic changeover regulator:
Forklift cylinder valves:
Butane Cylinders, Non-domestic
Butane cylinders only allowed indoors:
- Where outdoor propane supply not possible
- Must have self-closing valves
- Maximum 4 cylinders
- Fire detection system needed in area
- Not allowed in basements
- Restricted public access only
Butane Cylinders: Dealer Storage
- Covered by IS 3213
- Use simplified Flogas "Guide to the Code
of Practice for the Storage of LPG Cylinders and Cartridges"
Propane Cylinders, Non-domestic
- Cylinders not indoors
- Cylinders upright, if necessary protected
from falling over (e.g. chains, close-fitting cages)
- Cylinders on firm, level surface, not
below ground level
- Minimise or eliminate unconnected spare
cylinders
- Cylinders in a well-ventilated area (not
defined!), must meet separation distances (see later)
- Cylinders in a recess or on rooftops
are special cases (refer to IS 820 Annex B)
Propane Cylinders: Distances From Boundaries
- Where the boundary is a wall, no separation
distance is required UNLESS the wall is part of a building
AND over 400 Kg of gas is involved: in this case, 1m
separation distance is required
- Where the boundary is a fence or wooden
building, a separation distance of 1m for up to 400Kg
of gas is required and 3m if over 400 Kg. Propane Cylinders:
Minimum Horizontal Separation Distances
| Distance (metres) |
Feature or hazard |
| 1.0 |
Window, door, air-vent, balanced-flue terminal,
trapped drain |
| 1.5 |
Parked motor vehicle, fixed sources of ignition,
unprotected electrical equipment, flammable / combustible
material |
| 3.0 |
Untrapped drain or unsealed gully, bund for bulk
flammable liquid storage, opening to cellar / basement,
corrosive / toxic / oxidising material |
| 6.0 |
Mechanical air intake |
Note 1: Any opening into chimneys or air
intakes shall be at least 1m above the level of the top
of any cylinder.
Note 2: Other openings above any cylinder
shall be at least 0.3m above the top of any cylinder.
Propane Cylinders: Non-domestic
Propane cylinders only allowed indoors:
- For portable or mobile equipment
- Restricted public access only
- Must be removed when not in use
Forklift Cylinders Forklift Cylinders
- Must be kept the right-way up especially
when horizontal on a forklift
- Ensure locating pins are provided on
forklift cylinder carriage
- Check condition of hoses
- Storage of spare cylinders governed
by IS 3213:
- Outdoors in well-ventilated position,
keep upright
- If public access, use a cage
- For up to 400 Kg, keep 1m from boundaries
and fixed sources of ignition, but can be kept up
against a boundary wall
- If filled from a tank, check IS 3216
Part 1
Forklift cylinder on forklift truck:
Inspecting Forklift Cylinders
- Only user-owned forklift cylinders need
inspection, all others are checked at the cylinder filling
plant.
- Reject forklift cylinders if:
- Leak on valve outlet or seal not
in place
- Ullage gauge (max fill) not working
- Contents gauge not working (tilt
cylinder over)
- Any pressurised part of cylinder
has dent, bulge, crack, gouge or badly rusted
- Base ring badly damaged (unstable
/ danger of toppling over)
- Over 15 years since last test date
- Have cylinder repaired by cylinder supplier
or LPG supplier
- Customer must arrange annual inspection
of filling system (required for all liquid-offtake installations)
Further Information
