Basic Introduction

1. A floor drain is a drainage fixture that connects the floor surface to the drainage piping system.
2. The distinctive characteristic of a floor drain is the nature of the substances it handles: it drains floor water, liquid residues, solid particles, fibrous materials, hair, and easily accumulated sediment.
3. The primary functions of a floor drain include:
Preventing odors, preventing blockages, deterring cockroaches, preventing the spread of viruses, preventing backflow, and preventing drying out (this last point primarily applies to water-seal type floor drains).
The quality of a floor drain is primarily evaluated based on four criteria: drainage speed, odor-blocking effectiveness, ease of cleaning, and durability (specifically regarding designs that do not rely on mechanical components).

Understanding Floor Drains

A floor drain should possess four key qualities: rapid drainage, odor prevention, clog resistance, and ease of cleaning.
As the name implies, a "floor drain" is fundamentally designed to drain water. However, the era where a floor drain served the singular function of merely letting water pass has long since passed.
Beyond simply draining water quickly, the most critical feature of a floor drain is its resistance to clogging; otherwise, the constant need for cleaning creates a perpetual source of trouble.
The market is flooded with a vast array of floor drain varieties, with prices ranging from a mere 3 to 5 yuan up to over 100 yuan. Yet, finding one that genuinely delivers effective odor prevention remains a challenge. While many products claim to be "odor-proof," their actual performance can only be verified through firsthand experience after installation.
The Importance of Floor Drains
Indoor air quality is a matter that weighs heavily on the minds of countless households—and indeed, on the minds of the nation's leaders.
Between June and September 2001, two Vice Premiers of the State Council issued directives on three separate occasions. They emphasized that issues concerning the residential environment have a direct bearing on residents' physical health and must be accorded the highest priority, subsequently mandating relevant government departments to conduct research into the matter. Concurrently, relevant ministries—including the Ministry of Construction, the Ministry of Health, the General Administration of Quality Supervision, Inspection and Quarantine, and the State Environmental Protection Administration—were working intensively to formulate pertinent regulations and standards. The national standard for "Floor Drains" (GB/T 27710-2011) officially came into effect on July 1, 2012.
68% of Human Illnesses Are Linked to Indoor Pollution
In June 1997, an outbreak of Legionnaires' disease occurred in an office building in Beijing. Within a short period, 108 individuals within the building fell ill—a morbidity rate of 34.62%. Patients presented with generalized body aches; some also experienced tonsillitis, diarrhea, and high fever.
Legionnaires' disease was first identified in July 1976 during a convention of military veterans in Philadelphia, USA—hence its name. The disease is primarily caused by Gram-negative bacilli; specifically, *Legionella pneumophila* colonizes and proliferates in water sources. It is primarily transmitted through the cooling water in air conditioning cooling towers, air supply ducts, faucets, showerheads, and similar conduits. Symptoms of the disease include fever, chills, headaches, difficulty breathing, vomiting, and diarrhea—symptoms that closely resemble those of pneumonia. According to reports, there have been seven recorded outbreaks of Legionnaires' disease domestically. In fact, over 300 types of pollutants can be detected in the air, and approximately 68% of human illnesses are linked to indoor pollution.
Song Guangsheng, Director of the China Indoor Decoration Association, analyzes that indoor environmental pollution is primarily caused by the improper use of renovation materials. First, there is unreasonable design—using a single material excessively within a room (e.g., installing composite flooring over a large area), which leads to formaldehyde levels exceeding safety limits. Second, there are unreasonable construction practices—traditional methods often fail to account for indoor environmental issues (e.g., laying blockboard beneath composite flooring, applying clear varnish to walls to prevent cracks, or manufacturing traditional furniture without edge banding), all of which contribute to air pollution. Third, there is the selection of substandard renovation materials.
The 2003 SARS outbreak at the Amoy Gardens residential complex in Hong Kong was directly attributed to defective floor drains; this incident serves as compelling proof of the critical importance of floor drains.
**Key Selection Criteria**
1) The standard CJ/T 186-2003 applies exclusively to floor drains used in general industrial and civil buildings; it does not apply to specialized locations—such as blast-resistant floor drains designed for civil defense projects, or explosion-proof floor drains designed for petrochemical facilities. For floor drains intended for such specialized locations, in addition to referencing this standard, the products must also comply with the specific technical requirements of the relevant industry.
2) The water seal is one of the most critical features of a water-sealed floor drain. When making a selection, it is essential to verify whether the product's water seal depth meets the minimum requirement of 50 mm. Side-wall floor drains, floor drains with mesh frames, and sealed-type floor drains typically do not incorporate a built-in water seal; conversely, anti-overflow floor drains and multi-channel floor drains generally *do* feature a water seal. Therefore, when selecting these products, one should consult the manufacturer's technical specifications to confirm the details.
For floor drains that do not feature a built-in water seal, a P-trap (or water trap) with a water seal depth of no less than 50 mm must be installed within the drain's discharge piping. This component may be supplied by the floor drain manufacturer or installed by the construction team responsible for the floor drain installation.
3) The height of the floor drain grate surface should be adjustable, with an adjustment range of no less than 35 mm, to ensure that—once the floor finishing work is complete—the top surface of the floor drain sits flush with the surrounding floor level. Floor drains should be equipped with a waterproof flange (or wing ring) to ensure effective waterproofing at the point where the drain is installed into the structural floor slab.
For floor drains situated in underground parking garage vehicle lanes or other areas subject to heavy loads, the structural strength of the drain grate must be sufficient to withstand the corresponding load requirements. 4) The structure of a water-seal floor drain must be rational and ensure smooth flow, preventing debris within the drainage water from easily settling out. The cross-sectional area of ​​the water passage in each component should ideally exceed the cross-sectional area of ​​the discharge pipe, and the minimum clear width of the flow channel cross-section should not be less than 10 mm.
5) There are three methods for connecting floor drains: socket-and-spigot, threaded, and clamp connections. The dimensions of the connection ports should be determined in accordance with current relevant national regulations.
6) Priority should be given to the use of odor-proof floor drains. Areas where drainage is not required need not be equipped with floor drains. Construction projects where floor drains have been installed but lack the necessary water traps (P-traps) shall not be approved for final completion.
Aesthetics
In "dry zones"—areas where the floor remains largely dry—floor drains can be positioned in inconspicuous locations, as there will be minimal standing water on the floor. Conversely, in "wet zones"—such as shower areas—ensuring unimpeded drainage is paramount. Consequently, the floor drain cannot be concealed; in fact, it must be positioned approximately 10 mm *below* the surrounding floor level, which may not be aesthetically pleasing. In such instances, creative design solutions can be employed to enhance the visual appeal. For example, the floor drain can be visually "hidden" by installing a suspended, open-work metal decorative cover over it; this element not only harmonizes with the interior design scheme but also serves a practical function as a "secondary filter." Alternatively, the flooring surrounding the drain can be paved with mosaic tiles arranged in curved or sloping patterns; such shapes are not only visually attractive but also facilitate faster water flow.
Furthermore, one can capitalize on the fact that bathroom floors are often slightly raised (to accommodate plumbing) by creating a small, recessed "pool" area centered around the floor drain.

Installation and Additions

Installation
First: Trim the pre-allocated drainage opening to ensure it fits perfectly with the floor drain you have purchased. This step is necessary because the drainage openings left by developers at the time of property handover are typically quite large. Specifically, the aperture size of the floor drain grate should be kept between 6 and 8 mm; this prevents debris such as hair, sludge, and sand particles from entering the drain.
Second: When installing a multi-channel floor drain, the inlets should be utilized and configured according to the specific requirements of the site. A multi-channel floor drain—when paired with a multi-functional adapter—can accommodate drainage from multiple sources simultaneously (including washbasins, bathtubs, washing machines, and the floor itself). This structural design effectively resolves situations where a single sewer outlet needs to serve multiple drainage points.
Retrofitting
There are generally two methods for installing a new floor drain in a location where one did not previously exist: First, raise the floor level to allow for the routing of drainage pipes; second, core through the concrete floor slab to lay new drainage piping.

Material

The primary materials include cast iron, PVC, zinc alloy, ceramic, cast aluminum, stainless steel, brass, and copper alloy.
1. Engineering Plastics: Widely used in engineering applications; inexpensive and cost-effective.
2. Cast Iron: Low cost; prone to rusting; aesthetically unappealing; rust tends to trap dirt and grime, making it difficult to clean.
3. PVC: Low cost; susceptible to deformation caused by temperature fluctuations; poor resistance to scratches and impact; aesthetically unappealing.
4. Zinc Alloy: Low cost; highly susceptible to corrosion.
5. Ceramic: Low cost; corrosion-resistant; lacks impact resistance.
6. Cast Aluminum: Mid-range price; lightweight; relatively coarse surface texture.
7. Stainless Steel: Moderately priced; aesthetically pleasing; durable.
8. Copper Alloy: Moderately priced; highly practical.
9. Brass: Heavyweight; high-end material with a higher price point; surfaces can be treated via electroplating.