Based on the provided reference, RL (Reduced Level) and FFL (Finished Floor Level) are prefixes used on drawings to avoid confusion when indicating levels that might be mistaken for other numbers or symbols, such as room numbers or dimensions. They both essentially serve the same purpose: to clearly denote a specific elevation. Therefore, the "difference" lies more in the convention and preference within a project or organization rather than a fundamental distinction in their meaning.
Here's a breakdown:
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RL (Reduced Level): Indicates a level relative to a specific datum point (a reference point with a known elevation). The number following "RL" specifies the height above that datum.
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FFL (Finished Floor Level): Indicates the level of the finished floor surface. Similar to RL, it refers to the height above a specific datum.
Essentially, both terms specify a height in relation to a benchmark, and their usage is largely interchangeable depending on industry standards and project-specific conventions. The key is consistency in using either RL or FFL throughout the project documentation.
In summary, while both RL and FFL are prefixes used to denote levels or elevations on drawings, they are fundamentally the same, and the choice between them is based on convention and preference within a project, firm, or industry.
