Different types of gas filter tanks are specially designed and matched products according to different anti-toxicity performance requirements. When used, they are connected with gas ducts and gas masks. In different toxic environments, different types (labels) of filter tanks can be replaced directly. The product has obvious label, good filtration toxicity, low resistance, good air tightness and convenient replacement. In toxic environment, where the concentration of toxic gas is less than 18% and the concentration of toxic gas is more than 2%, all types of filter gas masks can not play a protective role, so air supply and oxygen supply masks should be used instead.
Type and colour of filter parts compared with original standard
Table 1 Types of filters compared with the original standard
| GB2890-2009 Type of filter | Filters specified in the new standard Types of protective gases | GB2890-1995 Type of gas filter | GB2890-2009 Provision of color marking for filter parts | GB2890-1995 Provision for marking of gas filter tank |
| A | Used to protect against organic gases or vapors | Number 3 | brown | brown |
| B | Used to protect inorganic gas or steam | Number 1 | gray | green |
| E | Used to protect sulfur dioxide and other acid gases or vapors | Number 7 | yellow | yellow |
| K | Organic Derivatives for Protecting Ammonia and Ammonia | Number 4 | green | gray |
| CO | Protection against carbon monoxide gas | Number 5 | white | white |
| Hg | Used to protect mercury vapor | Number 6 | gules | black |
| H2S | Used to protect hydrogen sulfide gas | Number 8 | blue | blue |
| T | Used to protect formaldehyde gas | Number 9 | Violet | green |
List of Performance and Usage of Filter Parts (Poison Cans, Boxes)
Note: The label of the filter is composed of the type of the filter (such as A, B, etc.), the level of the filter (such as 2, 3, etc.), and the performance level of the filter (such as P1, P2, P3). The letters P, D, Z and T represent common filters, multi-functional filters, comprehensive filters and special filters, respectively.
| Filter sign | Filtering level | Colour marking of filter parts | Protected object | Test medium |
Protection time min | Concentration of mg/L |
| P- A-2 | 2 | brown | Organic gas or steam | benzene | ≥70 | 9.7 |
| P-B-2 | 2 | gray | Inorganic gas or steam | Hydrocyanic acid | ≥27 | 3.4 |
| P-K-2 | 2 | green | Ammonia and its organic derivatives | ammonia | ≥25 | 2.1 |
| P-E-2 | 2 | yellow |
| sulfur dioxide | ≥23 | 8.0 |
| Z-B-P3-2 | 2 | gray | Inorganic Gas or Steam Smoke | Hydrocyanic acid | ≥27 | 3.4 |
| Pink | ||||||
| P-A-3 | 3 | brown | Organic gas or steam | benzene | ≥115 | 16.2 |
| P-B-3 | 3 | gray | Inorganic gas or steam | Hydrocyanic acid | ≥63 | 5.6 |
| P-K-3 | 3 | green | Ammonia and its organic derivatives | ammonia | ≥60 | 3.6 |
| P-CO-3 | 3 | white | CO gas | CO | ≥100 | 5.8 |
| P-Hg-3 | 3 | gules | Protection against mercury vapor | mercury | 4800 | 0.01 |
| P-E-3 | 3 | yellow | Sulfur dioxide and other acid gases or vapors | sulfur dioxide | ≥30 | 13.3 |
| P- H2S -3 | 3 | blue | Hydrogen sulfide gas | Hydrogen sulfide | ≥110 | 7.1 |
| Z-B-P3-3 | 3 | gray | Inorganic Gas or Steam Smoke | Hydrocyanic acid | ≥63 | 5.6 |
| Pink | ||||||
| Z-B/CO -P3-4 | 4 | ash | Inorganic gases, steam, smoke and carbon monoxide | Hydrocyanic acid | ≥90 | 11.2 |
| white | ||||||
| Pink | CO | ≥150 | 5.8 | |||
| Z-A -P3-4 | 4 | brown | Organic gases or vapors, fumes | benzene | ≥135 | 32.5 |
| Pink | ||||||
| Z-K -P3-4 | 4 | green | Ammonia and its organic derivatives, smoke | ammonia | ≥55 | 7.1 |
| Pink | ||||||
| Z-E -P3-4 | 4 | yellow | Sulfur dioxide and other acidic gases or vapors, fumes | sulfur dioxide | ≥30 | 26.6 |
| Pink | ||||||
| P-B-1 | 1 | gray | Inorganic gas or steam | Hydrocyanic acid | ≥25 | 1.1 |
| P-A-1 | 1 | brown | Organic gas or steam | benzene | ≥45 | 5.0 |
| P-K-1 | 1 | green | Ammonia and its organic derivatives | ammonia | ≥25 | 0.76 |
| P-E-1 | 1 | yellow | Sulfur dioxide and other acid gases or vapors | sulfur dioxide | ≥30 | 2.7 |
| D-K/H2S-1 | 1 | green |
Ammonia and its organic derivativesHydrogen sulfide | ammonia | ≥25 | 0.76 |
| blue | Hydrogen sulfide | ≥35 | 1.4 |