Environmental design criteria

Use these environmental design criteria to ensure that your data center environment provides optimal conditions for your server operation.

The following environmental specifications are based on an altitude 1800 m (5906 ft above sea level). Some systems have more restrictive requirements on temperature, moisture, and altitude. For more information, see the individual system specifications.

Airborne particulates (including metal flakes or particles) and reactive gases that act alone or in combination with other environmental factors such as humidity or temperature might pose a risk to the server. Risks that are posed by the presence of excessive particulate levels or concentrations of harmful gases include damage that might cause the server to malfunction or cease functioning altogether. The environmental specifications present limits for particulates and gases that are intended to avoid such damage. The limits must not be viewed or used as definitive limits because numerous other factors, such as temperature or moisture content of the air, can influence the impact of particulates or environmental corrosives and gaseous contaminant transfer. In the absence of specific limits that are presented in the environmental specifications, you must implement practices that maintain particulate or gas levels that are consistent with the protection of human health and safety. If IBM determines that the levels of particulates or gases in your environment have caused damage to the server, IBM might condition provision of repair or replacement of servers or parts on the implementation of appropriate remedial measures to mitigate such environmental contamination. Implementation of such remedial measures is a customer responsibility.

Table 1. Operating environment⁵
Characteristics	Environment
Recommended temperature range¹	18°C (64.4°F) – 27°C (80.6°F)⁴
Low-end moisture	5.5°C (41.9°F) dew point
High-end moisture	60% relative humidity or 15°C (59°F) dew point
Gaseous contamination	Severity level G1 according to ANSI/ISA 71.04-1985², which states that the reactivity rate of copper coupons is fewer than 300 Angstroms per month (Å/month, ≈ 0.0039 μg/cm2-hour weight gain).⁶ In addition, the reactivity rate of silver coupons is less than 200Å/month (≈ 0.0035 μg/cm²-hour weight gain).⁷ The reactive monitoring of gaseous corrosivity must be conducted approximately 5 cm (2 in.) in front of the rack on the air inlet side at one-quarter and three-quarter frame height off the floor or where the air velocity is much higher.
Particulate contamination	Data centers must meet the cleanliness level of ISO 14644-1 class 8. For data centers without airside economizer, the ISO 14644-1 class 8 cleanliness might be met by any of the following filtration methods: The room air might be continuously filtered with MERV 8 filters. Air entering a data center might be filtered with MERV 11 or preferably MERV 13 filters. For data centers with airside economizers, the choice of filters to achieve ISO class 8 cleanliness depends on the specific conditions present at that data center. The deliquescent relative humidity of the particulate contamination must be more than 60% RH.³ Data centers must be free of zinc whiskers.⁸
Notes: The data is from ASHRAE Thermal Guidelines for Data Processing Environments, third edition (2012). For extended periods of time, information technology (IT) manufacturers recommend that data center operators maintain the recommended environment for maximum reliability. The allowable environment is where IT manufacturers test their equipment operation to verify that the equipment operates. This testing is not a statement of reliability of the IT equipment, but one of functionality of the IT equipment within the tested environment. See Table 2 and Table 3 for the allowable environment. ANSI/ISA-S71.04. 1985. Environmental conditions for process measurement and control systems: Airborne contaminants, Instrument Society of America, Research Triangle Park, NC, 1985. The deliquescent relative humidity of particulate contamination is the relative humidity at which the dust absorbs enough water to become wet and promote ionic conduction. For ambient temperatures that exceed 25°C (77°F), the acoustical noise levels of the system might increase as the speed of the air moving devices increases. For acclimation considerations for IT equipment, see Acclimation. The derivation of the equivalence between the rate of copper corrosion product thickness growth in Å/month and the rate of weight gain assumes that Cu₂S and Cu₂O grow in equal proportions. The derivation of the equivalence between the rate of silver corrosion product thickness growth in Å/month and the rate of weight gain assumes that Ag₂S is the only corrosion product. Surface debris is randomly collected from 10 areas of the data center on a 1.5 cm diameter disk of sticky electrically conductive tape on a metal stub. If examination of the sticky tape in a scanning electron microscope reveals no zinc whiskers, the data center is considered free of zinc whiskers.

Table 2. Allowable environment (product operating)
Classes	Product operations
Classes	Dry-Bulb temperature	Humidity range (non-condensing)	Maximum dew point (DP)	Maximum elevation	Maximum rate of change
A1	15°C - 32°C (59°F - 90°F)	20% - 80% RH	17°C (63°F)	3050 m (10000 ft)	5°C per 20 hours
A2	10°C - 35°C (50°F - 95°F)	8% - 80% RH	21°C (70°F)	3050 m (10000 ft)	5°C per 20 hours
A3	5°C - 40°C (41°F - 104°F)	-12°C (10°F) DP and 8% - 85% RH	24°C (75°F)	3050 m (10000 ft)	5°C per 20 hours
A4	5°C - 45°C (41°F - 113°F)	-12°C (10°F) DP and 8% - 90% RH	24°C (75°F)	3050 m (10000 ft)	5°C per 20 hours
B	5°C - 35°C (41°F - 95°F)	8% - 80% RH	28°C (82°F)	3050 m (10000 ft)	N/A
C	5°C - 40°C (41°F - 104°F)	8% - 80% RH	28°C (82°F)	3050 m (10000 ft)	N/A

Table 3. Allowable environment (product power off)
Classes	Product power off
Classes	Dry-Bulb temperature	Relative humidity (RH)	Maximum dew point
A1	5°C - 45°C (41°F - 113°F)	8% - 80%	27°C (81°F)
A2	5°C - 45°C (41°F - 113°F)	8% - 80%	27°C (81°F)
A3	5°C - 45°C (41°F - 113°F)	8% - 85%	27°C (81°F)
A4	5°C - 45°C (41°F - 113°F)	8% - 90%	27°C (81°F)
B	5°C - 45°C (41°F - 113°F)	8% - 80%	29°C (84°F)
C	5°C - 45°C (41°F - 113°F)	8% - 80%	29°C (84°F)

Table 4. Nonoperating environment²
Characteristics	Environment
Temperature	5°C (41°F) – 45°C (113°F)
Relative humidity	8% – 80%
Dew point	Less than 27°C (81°F)
Gaseous contamination	Severity level G1 according to ANSI/ISA 71.04-1985¹, which states that the reactivity rate of copper coupons is fewer than 300 Angstroms per month (Å/month, ≈ 0.0039 μg/cm²-hour weight gain).³ In addition, the reactivity rate of silver coupons is less than 200Å/month (≈ 0.0035 μg/cm²-hour weight gain).⁴ The reactive monitoring of gaseous corrosivity must be conducted approximately 2 in. (5 cm) in front of the rack on the air inlet side at one-quarter and three-quarter frame height off the floor or where the air velocity is much higher.
Notes: ANSI/ISA-S71.04. 1985. Environmental conditions for process measurement and control systems: Airborne contaminants, Instrument Society of America, Research Triangle Park, NC, 1985. The IT equipment acclimation period is 1 hour per 20°C (68°F) of temperature change from the shipping environment to the operating environment. The derivation of the equivalence between the rate of copper corrosion product thickness growth in Å/month and the rate of weight gain assumes that Cu₂S and Cu₂O grow in equal proportions. The derivation of the equivalence between the rate of silver corrosion product thickness growth in Å/month and the rate of weight gain assumes that Ag₂S is the only corrosion product.

Table 5. Shipping and storage environment
Characteristics	Shipping environment	Storage environment
Temperature	-40°C to 60°C (-40°F to 140°F)	1°C – 60°C (33.8°F - 140°F)
Relative humidity	5% – 100% (no condensation)	5% – 80% (no condensation)
Wet bulb	Less than 29°C (84.2°F)	Less than 29°C (84.2°F)
Shipping package	IBM-approved Vapor barrier bag with desiccant	IBM-approved Vapor barrier bag with desiccant
Notes: Solid-state drives (SSD) have the following restrictive limits for data retention: Do not exceed 60°C (140°F). Do not store at 60°C (140°F) or more for over 30 days when new. Do not store at 37.8°C (100°F) or more for over 180 days when new. Do not store at 60°C (140°F) or more for over 6 days when relocating (cumulative time at the specified temperature). Do not store at 37.8°C (100°F) or more for over 90 days when relocating. Ensure that you backup your data first, if applicable, before shipping.

Air quality

Many systems are installed in environments other than the typical data center, business office, or clean industrial location. These environments might exhibit various temperatures, relative humidity, and levels of airborne particles or corrosive gases. IBM® systems are designed to work within the environmental specifications that are shown in the previous tables unless otherwise noted on an individual system specification.

An environment is considered unacceptable when the temperature, relative humidity, corrosive gases, or solid particles in the air exceed specific limits set by IBM. Equipment that operates in environments that are classified as unacceptable might be subject to degraded performance and permanent damage if the equipment is not designed for such environments.

Contaminants

Systems are being installed in increasingly diversified industries. Some of these industries, as a by-product of their processes, cause the atmosphere to contain measurable quantities of gases and solid particles that are potentially harmful to electronic equipment. Urban areas that are highly industrialized might have levels of gases and solid particles that cause an unacceptable environment exposure to exist throughout an entire area.

IBM is concerned with two classes of atmospheric contaminants; solid particles and gases. Solid particles in the air are referred to as particulates. Water vapor can combine with these tiny, solid particles and form compounds. Such matter is said to be hygroscopic. It can be harmful, depending on the particulate composition. Gases can form harmful acids or bases when combined with water. Because of the ability to absorb moisture, the relative humidity and temperature are significant factors in an unacceptable environment.

High concentrations of gases, such as sulfur dioxide, nitrogen dioxide, ozone, and acidic gaseous chlorine, which are associated with industrial processes, are known to cause corrosion and failure of electronic components. In addition to gases, some industrial processes produce particulate contamination. These particles can settle (in the form of dust) in surrounding areas even though the process that produces the particles might be some distance away.

Industries that are engaged in processing petroleum, chemicals, primary metals, food, mining, and paper have a higher probability of encountering an unacceptable environment. However, contamination can be a result of construction, cleaning, or other activities that can occur anywhere.

A visual inspection is the first step in determining the likelihood of contamination. Some indicators of an unacceptable environment might include corrosion of metal such as door handles and hinges. Often, the presence of contaminants can be determined by odor as in the case of chlorine or sulfur, which have a distinctive smell. Observe whether a heavy layer of dust settles on surfaces, especially in the primary metals industry. This dust is often conductive and can create electrical arcing or short circuits if drawn into electronic equipment.

To determine adherence to IBM requirements for gases and particulates, laboratory techniques are necessary. Testing for gases and particulates involves special equipment and procedures. Contact your IBM installation planning representative for guidance.

If the environment is contaminated, IBM can also provide guidance on remediation, prevention, and control. Recommended solutions might include, but are not limited to, room pressurization, tighter relative humidity control, filtration, maintenance, and monitoring.

Last updated: Thu, April 16, 2020