How do gas input ratings at sea level differ from those at higher elevations?

Gas input ratings are indeed higher at sea level compared to those at higher elevations primarily due to the atmospheric pressure differences. At sea level, the atmospheric pressure is greater, which allows for a higher mass flow of gas into combustion appliances. This higher pressure means that more gas is available to mix with air for combustion, producing greater heat output.

As the elevation increases, atmospheric pressure decreases, leading to a reduction in the density of the gas-air mixture entering combustion devices. This means that at higher elevations, the same appliance will have a lower gas input rating because there is less gas available per unit of volume. This drop in pressure affects the combustion efficiency and can lead to incomplete combustion if adjustments are not made to compensate for the lower pressure.

Therefore, understanding this relationship between elevation and gas input ratings is crucial for ensuring optimal performance of gas-fired appliances in various geographical locations.