Environmental Sensitivities

Building Biology and Mold Exposure Guidelines

A structured reference combining SBM-2024 sleeping-area guidelines, ISEAI mold-assessment principles and the Shoemaker HERTSMI-2 framework.

Source frameworks

Keep each framework in its proper context.

These tools organize environmental information for discussion with a qualified professional. They are not diagnostic instruments.

This page presents several distinct frameworks. SBM-2024 provides precautionary Building Biology guidelines for sleeping areas. ISEAI provides professional guidance for assessing indoor environments in people with mold-related illness. HERTSMI-2 is a building index used within the Shoemaker/CIRS framework to support re-entry decisions for previously affected individuals. EPA and Health Canada recommendations are presented separately as public-health guidance on moisture, cleanup and indoor air. These frameworks must be identified separately and must not be presented as interchangeable legal, regulatory or universal safety standards.

Results should be interpreted within the framework that produced them. A measurement or score does not by itself identify every exposure source, characterize every room or diagnose an occupant.

SBM-2024

Precautionary Building Biology categories for sleeping-area environmental measurements and observations.

ISEAI

Professional mold-assessment principles that place testing within building, moisture, HVAC and source investigation.

Shoemaker/HERTSMI-2

A focused building index and score interpretation used within the Shoemaker/CIRS framework.

SBM-2024

SBM-2024 category definitions and principles.

The values are recommendations rather than legally binding exposure limits.

General principles

  • The values are designed primarily for sleeping areas.
  • They are precautionary guideline values.
  • They are recommendations rather than legally binding exposure limits.
  • Any risk reduction is considered worthwhile.
  • Nature and minimally polluted conditions are treated as the ultimate reference.
  • Multiple elevated exposures can justify a more severe overall assessment.
  • Measurement sensitivity, accuracy, duration and sampling conditions matter.
  • Complex findings may require professional Building Biology measurement methods.
SBM-2024 measurements

EMF and electrical guidelines.

Body voltage is shown only as “with ground reference.” Measurement setup and reference conditions must be recorded.

SBM-2024 EMF and electrical category ranges

Supporting notes

  • AC electric-field and AC magnetic-field ranges apply primarily up to and around 50/60 Hz.
  • Predominant harmonics and higher-frequency electrical components from approximately 2 kHz to 1 MHz should be assessed more severely.
  • SBM states that factors of approximately 10–100 may be applied, with a stronger factor at higher frequencies.
  • No universal plug-in dirty-electricity-meter threshold is created here because SBM-2024 does not provide one.
  • Where AC magnetic fields fluctuate substantially, SBM recommends considering the 95th percentile of long-term measurements, especially nighttime measurements.
  • Radiofrequency values apply to peak readings from individual RF sources, including cellular signals, Wi-Fi/WLAN, DECT, Bluetooth and broadcast signals.
  • SBM recommends aiming for lower exposure when signals are clearly periodic, pulsed or broadband.
  • Static-electricity measurements apply to suspect materials, appliances near the body and dominant surfaces under the specified measurement conditions.
  • An unverified outlet ground and an independent verified ground reference are not necessarily interchangeable.
SBM-2024 measurements

Indoor-air and climate guidelines.

Use the published units and document the room, conditions, method and timing of each reading.

SBM-2024 indoor-air and climate category ranges

VOC interpretation

  • TVOC represents the sum of volatile organic compounds under the relevant analytical method.
  • The total should not be interpreted without considering the mixture.
  • When one hazardous, odorous, allergenic, irritating or carcinogenic substance or substance group predominates, SBM says the result should be rated more severely.
  • Special compounds that are poorly represented by a standard TVOC analysis may require separate testing.
  • Do not use the TVOC total to declare that every individual chemical is acceptable.

Humidity interpretation

Room relative humidity does not by itself establish the moisture condition of every material or surface. Cold surfaces, thermal bridges and concealed assemblies may experience higher local relative humidity or condensation than the central room sensor indicates.

Within SBM’s mold guidance, persistent high material moisture, high air humidity, cool surface temperatures and severe thermal bridges should be avoided.

SBM-2024 observations

Mold and moisture guidelines.

Visible area alone must not be presented as a complete mold assessment.

SBM-2024 mold observation category ranges

Mold principles

  • Mold growth should not be visible to the naked eye or through investigative instruments.
  • Contamination by mold spores or mold metabolites should not be present.
  • Particularly serious molds, deeper material growth and concerning species justify a more severe rating.
  • Indoor mold quantities in air, surfaces, house dust, cavities and materials should be lower than outdoor air or uncontaminated reference rooms.
  • Indoor mold species should be very similar to those outdoors or in uncontaminated reference rooms.
  • Particularly serious, toxigenic, allergenic or body-temperature-tolerant molds should be undetectable or only minimally detectable.
  • Mold metabolites such as mycotoxins, microbial VOCs and glucans should not contaminate the indoor environment.
  • Constantly high material moisture and air humidity should be avoided.
  • Cool surface temperatures and severe thermal bridges should be avoided.
  • Material water activity should not remain above 0.65 for prolonged periods.
  • Odor, discoloration, staining, previous water damage, building history, construction details, occupant concerns and laboratory findings may justify further investigation.
Client-side tool

Interactive SBM measurement classifier.

Enter one numeric measurement to see its category. The selector includes the supplied SBM-2024 measurements plus a clearly labeled LAADA practical RH screen.

For calculator boundary handling, exact shared thresholds are classified in the more precautionary adjacent category. The LAADA practical RH screen treats 30–50% as unflagged and readings above 50% through below 70% as slight.

Choose a measurement and enter a result to classify it.

ISEAI

ISEAI approach to mold testing.

Testing is one part of a broader building investigation.

ISEAI’s Indoor Environmental Professional materials describe mold testing as one part of a broader building investigation. The purpose of testing is to answer a defined environmental question, not to replace inspection, moisture assessment or source identification.

ISEAI mold-testing framework

ISEAI interpretation hierarchy

  1. Review building history and moisture history.
  2. Identify current or previous water entry.
  3. Inspect the building envelope, interior materials and HVAC system.
  4. Select tests that answer a defined question.
  5. Review individual species and concentrations rather than relying only on a composite score.
  6. Consider sample collection method, room selection, dust age and cleaning history.
  7. Integrate laboratory data with physical inspection findings.
  8. Verify that remediation corrected the moisture source and removed affected material and residual contamination.
Testing roles

ERMI and HERTSMI-2 roles.

Neither index locates every source or represents every room.

Within the ISEAI framework, ERMI and HERTSMI-2 results should not be interpreted in isolation. Individual species, concentrations, sampling conditions, building history, moisture findings and occupant susceptibility all contribute to interpretation.

ERMI and HERTSMI-2 comparison
Shoemaker/CIRS framework

Shoemaker framework and intended HERTSMI-2 use.

Score interpretations below are explicitly identified as Shoemaker framework interpretations.

  • HERTSMI-2 was designed for people previously sickened by water-damaged buildings.
  • It is intended to support decisions regarding occupancy or re-entry within the Shoemaker/CIRS framework.
  • The roster was developed from consecutive ERMI data.
  • Five species were selected and assigned weighted point ranges.
  • The result is a building index.
  • One sample cannot characterize every area of a building.
  • The score does not replace observation of symptoms or clinical laboratory findings following re-exposure.
  • The score does not locate the environmental source.
  • The page identifies score interpretations as “Shoemaker framework interpretations.”
HERTSMI-2 source scorecard notation

Units: Spore Equivalents per milligram of dust—Spore E./mg.

The Surviving Mold page spells the first species “Aspergillus penicilloides.” This page preserves that spelling from the official HERTSMI-2 material.

Client-side tool

Interactive HERTSMI-2 calculator.

Enter dust concentrations as nonnegative numbers. Blank fields count as zero but remain visibly marked as not entered.

For calculator completeness, the exact boundary values 500, 125 and 2,500 are assigned to the higher point band. The source scorecard displays the upper categories using greater-than symbols and does not separately state these exact boundary integers.

Total HERTSMI-2 score 0 / 50

Enter concentrations to calculate a Shoemaker/CIRS framework interpretation.

Reported study data

HERTSMI-2 score and observed relapse.

Reported relapse percentages among previously affected CIRS-WDB patients who re-entered buildings.

Accessible table fallback for reported relapse data

These percentages were reported in a 2016 analysis of previously affected CIRS-WDB patients. The reported endpoint was symptom relapse following re-entry under the study’s criteria. The data are specific to the studied clinical population and Shoemaker framework.

The study reported 807 HERTSMI-2 scores: 618 calculated from ERMI panels and 189 from HERTSMI-2-only testing.

Low scores were grouped as 0–10, indeterminate scores as 11–15 and high scores as greater than 15.

This chart is not an individualized probability calculator and does not predict an individual user’s medical outcome.

Public-health guidance

EPA and Health Canada recommendations.

Practical guidance for moisture control, cleanup and indoor-air decisions.

Use these recommendations as a practical starting point. EPA and Health Canada focus on controlling moisture, addressing visible or concealed mold and reducing avoidable indoor-air exposures. Their recommendations do not establish a universal mold test threshold, diagnose an occupant or replace a qualified building or clinical assessment.

EPA: control moisture and clean promptly.

  • Moisture control is the key to mold control. Clean up mold promptly and correct the water or moisture problem that allowed it to grow.
  • Dry wet or damp materials within 24–48 hours when possible. Keep indoor relative humidity below 60%, ideally between 30% and 50%.
  • Small areas of mold, roughly 10 square feet or less, can often be addressed by a homeowner who follows the EPA cleanup guidance.
  • Consider professional help for larger areas, extensive water damage, sewage or contaminated water, or suspected HVAC contamination. Do not operate an HVAC system known or suspected to be contaminated because it may spread mold.
  • Clean hard surfaces with detergent and water, then dry completely. Moldy porous materials such as carpet or ceiling tile may need to be discarded. Do not paint or caulk over moldy surfaces.
  • People with health concerns should discuss the situation with a healthcare professional before beginning cleanup.

Health Canada: prevent, inspect and remediate.

  • Repair leaks and water damage diligently, control indoor humidity and clean visible or concealed mold regardless of the species identified.
  • Keep relative humidity around 30%–50% using a hygrometer, ventilation, a dehumidifier or air conditioning as appropriate. Use kitchen and bathroom exhaust fans and vent dryers and cooking exhaust outdoors.
  • Start with a moisture history and visual inspection. Health Canada notes that there are no universal indoor mold exposure limits and that air fungal testing cannot by itself determine an occupant’s health risk.
  • Use the appropriate cleanup approach for the size and condition of the affected area. Larger, hidden, recurring or complicated problems may require a qualified professional.
  • These recommendations apply regardless of the mold species. Decisions should consider the building, the extent of moisture or mold and the needs of people who occupy the space.

How this relates to the other tables on this page. EPA’s and Health Canada’s practical 30%–50% relative-humidity range is not the same thing as the SBM-2024 category table above. The sources should be read as complementary but distinct: public-health guidance emphasizes prevention and remediation, while the other frameworks organize specific measurements or building-index interpretations.

Limitations

Interpretation notices.

Use these tools to organize questions, not to make a medical or universal building-safety determination.

Measurement limitations

  • A result depends on instrument sensitivity, accuracy, placement, reference point, duration and sampling conditions.
  • One reading cannot represent every room, concealed assembly, material or exposure source.
  • Visible mold area, dust testing and air sampling answer different questions.
  • Calculator boundary handling is a transparent implementation choice where the displayed source ranges share thresholds.

Clinical and professional limits

  • HERTSMI-2 results are building-index results and do not diagnose an occupant.
  • A Shoemaker/CIRS framework interpretation does not replace clinical evaluation or symptom observation after re-exposure.
  • SBM categories are precautionary Building Biology guidelines, not universal legal or medical limits.
  • Use a qualified professional for building investigation and discuss health concerns with a licensed clinician.

Medical disclaimer: This information is provided for general education and does not constitute medical advice, diagnosis or treatment. Environmental measurements and HERTSMI-2 scores cannot establish the cause of symptoms or determine a universal property status. Consult qualified building and healthcare professionals for decisions about your environment and health.

References

Primary framework sources.

Each source is identified by the framework or organization it represents.