Diseño de Instalaciones 1|FAU-UNT|14|Instalación de Gas|Clase 1-Parte 1

Main Ideas, Concepts, and Lessons

Course scope (Gas installations in low-complexity buildings)

• Learn the components of gas installations.
• Understand and manage regulations that govern layout and correct execution.
• Develop functional and economic plans for the installation.
• Learn the pipe-sizing calculation methodology.

Why gas installations require special responsibility

Faulty installations can cause serious accidents affecting health and life.

Key hazards discussed:

• Carbon monoxide inhalation (from combustion)
  • Can cause headaches, fainting, and death.
  • Risk increases with:
    • Poor installation condition
    • Insufficient ventilation
    • Appliances located in unsuitable places
  • Particularly dangerous because it cannot be detected by smell.
• Asphyxiation
  • Natural gas isn’t “toxic,” but high concentrations displace oxygen, causing unconsciousness and death.
  • Gas includes a chemical additive that gives it a characteristic odor to detect leaks.
• Explosion / fire
  • Occurs when a flammable gas cloud forms due to an undetected leak.
  • A spark (e.g., from a gas valve) can trigger ignition.

Regulatory compliance (example: Gasnor)

• Installation must comply with safety and hygiene regulations (named in the transcript: Gasnor).
• Regulations cover:
  • Pipe layout and installation requirements
  • Watertightness of pipes, fittings, and appliances
  • Ventilation of premises
  • Evacuation of combustion gases
  • Proper functioning requirements for appliances

Types of gas mentioned

• Natural gas (mostly methane)
  • Calorific value: ~9,000 kcal/h
  • Advantages: low operating cost, no storage, low installation cost, easy maintenance
• Bottled / liquefied gas
  • Used where there’s no natural gas network
  • Disadvantages: needs storage and is more expensive
• Rural / agro-industrial gas use
  • When bottled gas is hard/expensive to obtain, or where waste is used to produce gas

Basic gas supply infrastructure (high/medium pressure concepts)

• Gas is extracted under pressure, then treated and separated into usable components.
• Transport:
  • Large-diameter steel pipelines at high pressures + compression stations
• Regulation into cities:
  • Use regulating / stabilizing plants to reduce pressure for urban distribution.
  • Mention of Brazil’s typical urban distribution: grid pattern so an outage at one point doesn’t cut an entire area.
• Urban pipes:
  • Typically black iron (corrosion protected) or polyethylene
  • Medium pressure range: 0.05 to 2 kg/cm²
  • Installed roughly ~1 meter below sidewalks

---

Methodology / Instructions Presented (Detailed Bullet Format)

A) Home gas installation — key components and placement rules

Gas meter niche / box

• Residential gas meter housed in a niche with appliances, shut-off valves, and ventilation.
• If mains gas isn’t available: use a gas meter box alternative.

Home extension (external-to-internal connection)

• Function: connects the distribution line to the internal piping.
• Routing / placement rules:
  • Located ~20 cm outside the property line and meter area
  • Must run perpendicular to the property line
  • Must follow the shortest possible route
  • Must not interfere with other installations (storm drains, water connections, electrical connections)
  • Must avoid columns/trees
• Installation depth / embedding:
  • Buried ~30 cm deep or embedded in walls
• Prohibited condition:
  • Cannot pass through habitable rooms

Pressure regulator

• Needed because network gas is medium pressure, while appliances require low pressure.
• Reduces gas pressure via a valve with a flexible section (concept described in the text).

Gas meter

• Registers consumed gas volume (in cubic meters per hour).
• Must include:
  • Indicator / viewing window for reading
  • Location: above the property line in a niche
• Niche material:
  • Must be non-combustible
• Niche door:
  • Metal door with ventilation grilles
• Safety access:
  • Contains a valve operable only by authorized personnel
• Separation / clearance:
  • Must be at least 50 cm from other installations (especially electrical)
  • A shorter distance is allowed only when the room is ventilated via ducts to the outside

Internal gas piping (user responsibility)

• Installation/control/maintenance can use any approved material.
• Materials mentioned:
  • Galvanized iron (silver)
  • Epoxy-painted black plaster-coated iron (yellow)
  • Polyethylene pipes with a steel core for rigidity
  • Also mentions copper, aluminum, stainless steel pipes
• Laying / ground preparation:
  • Can be laid on natural ground if soil consistency allows
  • Otherwise: build a brick bed to prevent deformation
• Embedding / support rules:
  • Can be embedded in subfloor/walls or in walls
  • Common placement: around 1 meter high to separate from other installations
  • Must be fixed securely and not subjected to unnecessary stress
  • If walls are wood/plasterboard: pipes are screwed
  • If polyethylene: protect against elements
  • If metallic: protect against building-related risks (as stated)
  • Roof placement: supported on pillars spaced no more than 22.5 m, firmly attached
• Clearance from other installations:
  • Keep at least 15 cm away from others, especially electrical
• Crossing electrical:
  • If pipes/cables cross, interpose an electrical insulating element (overhead or in conduits)

Shut-off valves (per appliance)

• Purpose: quickly cut gas supply during leaks or repairs
• Characteristics:
  • Quarter-turn to full lock
  • Same diameter as the feeding pipe to the appliance
• Location:
  • Easily visible and accessible for quick operation

---

B) Appliance operation and combustion fundamentals

Combustion concept

• Combustion = chemical combination of gas fuel (carbon/hydrogen) with oxygen (from air), releasing heat/light.
• Requirements to start:
  • Need high ignition temperature (from an ignited source)
• Safety implication:
  • Produces carbon monoxide, which must be vented outside

Bunsen burner functioning (mixture formation)

• Gas enters via injector
• Air mixes with gas (primary air), exits through the burner
• Flame quality indicators for correct combustion:
  • Incandescent interior
  • Green intermediate cone
  • Colorless outer cone
• Fault indicator:
  • Yellowish flame suggests incorrect combustion

---

C) Classification of gas appliances by exhaust/venting method

• Ventless appliances

  • Use combustion air from the room
  • Discharge exhaust gases and heat back into the room
  • Examples mentioned: stoves, some infrared heaters

• Natural draft / open-chamber appliances

  • Combustion chamber open to the environment
  • Take combustion air from the room
  • Exhaust to the outside through ducts

• Balanced-flue appliances

  • Sealed combustion chamber
  • Take combustion air from outside
  • Exhaust combustion gases to outside as well
  • Examples mentioned: balanced-flue stoves and balanced-flue water heaters

---

D) Location and installation requirements for specific appliances mentioned

1) Ventless stove (cooking appliance)

• Positioning constraints:
  • Minimum 30 cm from any sanitary fixture
  • Not exposed to drafts
  • Must be supported on non-combustible surfaces
  • Cannot be embedded
• Room requirements:
  • Minimum room volume: 15 m³
  • Room must have air intake and exhaust openings for air renewal and carbon monoxide evacuation
• Installation notes (kitchen connection concept):
  • Burner connection rises to ~1 meter height; then branch/connection is made to the stove area; shut-off valve placed there

2) Instantaneous (tankless) domestic hot water heater

• Operation principle:
  • Heats water quickly using a heat exchanger coil
  • Main burner flame ignites
  • Pilot light always on; it ignites automatically when a hot water tap opens
  • Gas flow regulation depends on water consumption via a diaphragm valve linked to a spring
  • Capacity expressed in liters relates to temperature rise (20°C increase in 1 minute)
• Installation types by venting:
  • Natural draft (open-chamber)
    • Draws combustion air from surrounding environment through duct to outside
  • Balanced-draft
    • Sealed combustion chamber with double duct
    • One duct supplies primary air, other exhausts gases
• Placement / room requirements:
  • Burner height: between 15 and 18 m from floor level (as stated)
  • Cannot be outdoors and cannot be recessed
• Natural draft restrictions:
  • Not in bedrooms or bathrooms
  • Not above sinks, washbasins, or other sanitary fixtures
  • Room must have air intake openings
  • Room volume: at least 7 m³
  • Needs specific water pressure:
    • Height difference between base and highest fixture must be ≥ 2 m
    • If there is a branch line: ≥ 4 m
• Balanced-flue restrictions:
  • No ventilation restrictions mentioned (relative flexibility)

3) Constant storage water heater

• Construction / operation:
  • Metal tank protected against corrosion + thermal insulation/regulation
  • Thermostat controls burner to maintain constant temperature
  • Hot water maintained as cold mains enters
  • Heat exchange via base and combustion gas deflector duct
• Venting:
  • Natural draft
• Location requirements:
  • Room volume: at least 7 m³
  • Must be ventilated
  • Outdoor installation allowed only if recessed in a ventilated niche/vent
  • Not allowed in bedrooms or bathrooms

4) Space heating appliances (ventless infrared / radiant tube / convection heaters)

• Infrared heaters (ventless)

  • Ventless: uses room air and doesn’t exhaust via flue (as described)
  • Placement:
    • Can be placed in almost any room except bathrooms/hallways
    • Not above kitchen sinks/washbasins/laundry tubs
  • Room volume: minimum 15 m³
  • Air ventilation openings required
  • Heating capacity limit: ≤ 50 kcal/h per m³
  • Not advised to aim radiation toward people
  • Mainly used for outdoor/semi-covered areas; rarely for lower indoor spaces due to risk

• Radiant tube variant

  • Combustion chamber + black tube circulation
  • Heat exchange and radiation from the tube
  • Also described as used in outdoor spaces because it’s flueless

• Convection heaters

  • Can be natural draft or balanced draft
  • Heating principle:
    • Cold air enters → contacts combustion chamber → heats → exits at top
  • Performance / safety:
    • Economical
    • Balanced-draft described as safe
    • Low inertia: heats quickly, but room cools immediately after shutdown
    • Low efficiency: about 60% of consumed energy becomes heat
  • Placement:
    • Mount about 20 cm above floor level for air intake
    • Don’t hide/cover with shelves (avoid blocking hot air outlet)
    • Careful placement due to obstructing airflow and high outlet temperature
    • Child access must be controlled
    • Recommended positioning: ground floor and coldest areas (since hot air rises)
  • Natural draft restrictions:
    • Not in bedrooms or bathrooms (hallways allowed)
    • Rooms must have ventilation services
    • Room volume: ≥ 7 m³
    • Thermal power: ≤ 50 kcal/h per m³
  • Balanced-flue convection heaters:
    • Use ducts; don’t rely on ambient air
    • Don’t evacuate waste gases into the room
    • Fewer restrictions; can be placed in any room

---

E) Compare tankless vs storage water heaters (key consequences)

• Simultaneous use of multiple hot water outlets
  • Tankless: not possible (pressure loss)
  • Storage: allows multiple outlets concurrently
• Thermostat control
  • Storage: burner operation independent of water pressure/flow rate
  • Tankless: burner behavior depends on flow/pressure conditions
• Scale / clogging
  • Storage: does not have coils that become clogged (as claimed)
  • Tankless: tends to avoid (or differ) the coil issue; instead storage can accumulate residues
• Temperature behavior
  • Tankless: temperature can drop when cold water enters; if used quickly, may not reach set temperature
  • Tankless (text also says otherwise): tends to maintain temperature during consumption (final emphasis: stable as water is consumed)
• Heat loss
  • Tankless: loses heat through distribution pipe (as stated)
  • Storage: loses more heat due to being a storage element
• Maintenance
  • Storage: periodic cleaning required due to residue accumulation
  • Tankless: less frequent cleaning needs (as stated)

---

Speakers / Sources Featured

• Gasnor (regulatory body referenced for safety/hygiene regulations)
• No individual speakers’ names are identified in the provided subtitles.