SOP for Recording Temperature, RH and Pressure

In short: This illustrative SOP template covers recording room temperature, relative humidity (RH) and pressure differentials. Before use, the site’s quality unit must define which areas are monitored, the approved instruments, limits, monitoring intervals and response to alarms or excursions.

Objective

Describe a controlled method to record environmental conditions in manufacturing, storage or other designated areas where monitoring is required by the approved site procedure or product process.

Scope

Use this template only for areas identified in the site’s approved monitoring plan. It does not set universal temperature, RH or pressure-differential limits or frequencies. EU GMP requires premises conditions to be appropriate so they do not adversely affect products or equipment; for US cGMP, equipment for control of air pressure, humidity and temperature is required when appropriate to the drug-product operation (EudraLex Volume 4, Part I, Chapter 3, §3.3; 21 CFR 211.46(b)).

Temperature, RH and pressure-differential limits, monitoring points and recording intervals are set by each site. Base them on the storage requirements of the products and materials, the area classification and qualification, and a documented risk assessment, then record them in the approved area matrix (monitoring point, operating or idle state, instrument and units, limits, frequency, alarm and escalation instructions).

Example in-house criteria (not regulatory requirements). Typical values only; set your own from the basis above:

For sterile-product cleanrooms, EU GMP Annex 1 (2022), §4.14 gives a guidance value of a minimum 10 Pa pressure difference between adjacent rooms of different grade. The upper figure of 15 Pa and all other values in the table are in-house examples, not regulatory limits.

Responsibilities

• The trained person assigned to the area records readings and promptly reports alarms or results outside approved limits.
• The area supervisor ensures that monitoring is performed as required and that entries are complete.
• Quality Assurance (QA) approves the monitoring plan, limits and response procedure, and reviews records or investigations according to the site’s approved quality system.
• Engineering or maintenance maintains the environmental control system and monitoring instruments as assigned in controlled site procedures.

Example in-house criterion (not a pharmacopoeial requirement): The site procedure may assign a second person to verify entries or designate a reviewer for each area; record the approved assignment and review interval in the controlled document.

Procedure

Check the area and instruments

1. Confirm the area and monitoring point match the approved area matrix.
2. Check that the assigned thermometer/hygrometer, data logger or pressure indicator is identified, within its approved calibration or qualification period, and suitable for use. Follow the instrument’s approved operating procedure and manufacturer instructions.
3. Record the instrument identifier when required by the approved form. Do not use a damaged instrument or one with an expired or unclear status; report it and follow the site’s equipment procedure.
4. For pressure readings, use the specified measurement points and the room or equipment state described in the approved procedure. Do not change door, HVAC or zero settings to obtain a preferred result.

Record temperature and RH

1. At the approved interval, record the date and time, area, current temperature and RH, units, instrument identifier where required, and the operator’s identity.
2. Record minimum/maximum values only where the approved monitoring procedure requires them and the assigned device supports the required function. Follow the instrument procedure for retrieving and documenting those values.
3. If the area is not operating or an HVAC system is stopped, follow the approved status and monitoring instructions. Record an approved status code or explanation when applicable; do not silently omit a required reading or use an unexplained dash.
4. Make entries legibly and when the measurement is taken. Preserve the original entry if a correction is needed, and sign/date the correction with a reason where required by the documentation procedure (EudraLex Volume 4, Chapter 4, §§4.7–4.9).

Record pressure differentials

1. Confirm the measurement point, adjacent area, units and required operating state from the approved area matrix.
2. Read and record the indicated value as instructed by the approved instrument procedure. Document any alarm or unstable reading and follow the site’s escalation instructions.
3. Do not average, interpolate between scale divisions, reset a gauge, open a door or wait a fixed period after starting an air-handling unit unless the validated site procedure and instrument instructions specifically require that action.

For sterile medicinal-product cleanrooms within the scope of EU GMP Annex 1, §4.16 requires critical air-pressure differences to be continuously monitored and recorded, with an appropriate warning system; other air-pressure differences are monitored and recorded at regular intervals. Apply that provision only where the product and facility are within the Annex’s scope or the site has formally adopted it.

Respond to alarms or excursions

Record the observed condition and time, notify the responsible area lead and QA, and follow the approved deviation or alarm procedure. The investigation should assess the duration and potential effect on affected operations or product, document the decision, and identify any required corrective action.

Review and retain records

A designated reviewer should check records for completeness, unusual results, recurring trends, alarms and open investigations at the interval defined by the approved site procedure. Record the review and any follow-up.

Retain batch-associated GMP records for at least 1 year after the expiry date of the respective product batch. Under EU GMP Chapter 4 §4.11, batch documentation must be kept for one year after batch expiry or at least five years after Qualified Person certification, whichever is longer. For records covered by US cGMP, 21 CFR 211.180(a) also requires at least one year after batch expiry. Retain records longer when applicable local law or the marketing authorisation requires it.

Abbreviations

• AHU: Air-handling unit
• GMP: Good manufacturing practice
• QA: Quality Assurance
• RH: Relative humidity

Records

Use controlled forms or validated electronic records identified in the approved site document. The record should capture, as applicable, the area and monitoring point, date/time, operating status, temperature, RH, pressure value and units, instrument identity, operator, alarm or excursion details, reviewer and follow-up reference.

Frequently asked questions

What temperature, RH or pressure-differential limits should this SOP use?

Use the limits your site has set for the specific area and product process, based on product storage requirements, area classification/qualification and risk assessment. The cited GMP sections do not establish one value for every room; the table above gives example in-house criteria only.

Should the pressure differential be measured while the door is open?

Follow the approved method for the installed system. The measurement must use the specified area state and measurement points; this template does not direct operators to open a door or alter the reading.

What should an operator do when a reading is outside its limit?

Record the reading and follow the area’s approved notification and investigation procedure. Do not disregard a result solely because the room is idle; the site procedure must define how room status affects assessment.

How long should batch-associated monitoring records be kept?

At least one year after the expiry date of the respective product batch. EU GMP Chapter 4 §4.11 requires the longer of that period or five years after Qualified Person certification for batch documentation; 21 CFR 211.180(a) sets the US cGMP minimum for records within its scope.

Related reading

• Temperature and Relative Humidity Monitoring in the Pharmaceutical Industry
• SOP for Recording Temperature and Humidity of a Stability Chamber
• SOP for Recording Pressure Difference in a Manufacturing Area

References

• European Commission, EudraLex Volume 4, EU Guidelines for Good Manufacturing Practice for Medicinal Products for Human and Veterinary Use, Part I, Chapter 3: Premises and Equipment (revision dated 13 August 2014; effective 1 March 2015), especially §§3.1–3.3. Official text.
• European Commission, EudraLex Volume 4, Annex 1: Manufacture of Sterile Medicinal Products (revision dated 22 August 2022; effective 25 August 2023, except §8.123), §§4.14 and 4.16. Official text.
• European Commission, EudraLex Volume 4, Chapter 4: Documentation (revision 1, January 2011), §§4.7–4.11. Official text.
• U.S. Food and Drug Administration, Current Good Manufacturing Practice for Finished Pharmaceuticals, 21 CFR Part 211 (eCFR current through 14 October 2026), §§211.46(b) and 211.180(a). §211.46 · §211.180.